diff --git a/src/NzbDrone.Common.Test/Http/HttpClientFixture.cs b/src/NzbDrone.Common.Test/Http/HttpClientFixture.cs
index 2613c7e63..9438b4f89 100644
--- a/src/NzbDrone.Common.Test/Http/HttpClientFixture.cs
+++ b/src/NzbDrone.Common.Test/Http/HttpClientFixture.cs
@@ -6,6 +6,7 @@ using System.Linq;
 using System.Net;
 using System.Net.Http;
 using System.Threading;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NLog;
@@ -114,21 +115,21 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_execute_simple_get()
+        public async Task should_execute_simple_get()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/get");
 
-            var response = Subject.Execute(request);
+            var response = await Subject.ExecuteAsync(request);
 
             response.Content.Should().NotBeNullOrWhiteSpace();
         }
 
         [Test]
-        public void should_execute_https_get()
+        public async Task should_execute_https_get()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/get");
 
-            var response = Subject.Execute(request);
+            var response = await Subject.ExecuteAsync(request);
 
             response.Content.Should().NotBeNullOrWhiteSpace();
         }
@@ -140,47 +141,47 @@ namespace NzbDrone.Common.Test.Http
             Mocker.GetMock<IConfigService>().SetupGet(x => x.CertificateValidation).Returns(validationType);
             var request = new HttpRequest($"https://expired.badssl.com");
 
-            Assert.Throws<HttpRequestException>(() => Subject.Execute(request));
+            Assert.ThrowsAsync<HttpRequestException>(async () => await Subject.ExecuteAsync(request));
             ExceptionVerification.ExpectedErrors(1);
         }
 
         [Test]
-        public void bad_ssl_should_pass_if_remote_validation_disabled()
+        public async Task bad_ssl_should_pass_if_remote_validation_disabled()
         {
             Mocker.GetMock<IConfigService>().SetupGet(x => x.CertificateValidation).Returns(CertificateValidationType.Disabled);
 
             var request = new HttpRequest($"https://expired.badssl.com");
 
-            Subject.Execute(request);
+            await Subject.ExecuteAsync(request);
             ExceptionVerification.ExpectedErrors(0);
         }
 
         [Test]
-        public void should_execute_typed_get()
+        public async Task should_execute_typed_get()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/get?test=1");
 
-            var response = Subject.Get<HttpBinResource>(request);
+            var response = await Subject.GetAsync<HttpBinResource>(request);
 
             response.Resource.Url.EndsWith("/get?test=1");
             response.Resource.Args.Should().Contain("test", "1");
         }
 
         [Test]
-        public void should_execute_simple_post()
+        public async Task should_execute_simple_post()
         {
             var message = "{ my: 1 }";
 
             var request = new HttpRequest($"https://{_httpBinHost}/post");
             request.SetContent(message);
 
-            var response = Subject.Post<HttpBinResource>(request);
+            var response = await Subject.PostAsync<HttpBinResource>(request);
 
             response.Resource.Data.Should().Be(message);
         }
 
         [Test]
-        public void should_execute_post_with_content_type()
+        public async Task should_execute_post_with_content_type()
         {
             var message = "{ my: 1 }";
 
@@ -188,17 +189,16 @@ namespace NzbDrone.Common.Test.Http
             request.SetContent(message);
             request.Headers.ContentType = "application/json";
 
-            var response = Subject.Post<HttpBinResource>(request);
+            var response = await Subject.PostAsync<HttpBinResource>(request);
 
             response.Resource.Data.Should().Be(message);
         }
 
         [Test]
-        public void should_execute_get_using_gzip()
+        public async Task should_execute_get_using_gzip()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/gzip");
-
-            var response = Subject.Get<HttpBinResource>(request);
+            var response = await Subject.GetAsync<HttpBinResource>(request);
 
             response.Resource.Headers["Accept-Encoding"].ToString().Should().Contain("gzip");
 
@@ -208,11 +208,10 @@ namespace NzbDrone.Common.Test.Http
 
         [Test]
         [Platform(Exclude = "MacOsX", Reason = "Azure agent update prevents brotli on OSX")]
-        public void should_execute_get_using_brotli()
+        public async Task should_execute_get_using_brotli()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/brotli");
-
-            var response = Subject.Get<HttpBinResource>(request);
+            var response = await Subject.GetAsync<HttpBinResource>(request);
 
             response.Resource.Headers["Accept-Encoding"].ToString().Should().Contain("br");
 
@@ -230,7 +229,7 @@ namespace NzbDrone.Common.Test.Http
         {
             var request = new HttpRequest($"https://{_httpBinHost}/status/{statusCode}");
 
-            var exception = Assert.Throws<HttpException>(() => Subject.Get<HttpBinResource>(request));
+            var exception = Assert.ThrowsAsync<HttpException>(async () => await Subject.GetAsync<HttpBinResource>(request));
 
             ((int)exception.Response.StatusCode).Should().Be(statusCode);
 
@@ -243,7 +242,7 @@ namespace NzbDrone.Common.Test.Http
             var request = new HttpRequest($"https://{_httpBinHost}/status/{HttpStatusCode.NotFound}");
             request.SuppressHttpErrorStatusCodes = new[] { HttpStatusCode.NotFound };
 
-            var exception = Assert.Throws<HttpException>(() => Subject.Get<HttpBinResource>(request));
+            Assert.ThrowsAsync<HttpException>(async () => await Subject.GetAsync<HttpBinResource>(request));
 
             ExceptionVerification.IgnoreWarns();
         }
@@ -253,7 +252,7 @@ namespace NzbDrone.Common.Test.Http
         {
             var request = new HttpRequest($"https://{_httpBinHost}/status/{HttpStatusCode.NotFound}");
 
-            var exception = Assert.Throws<HttpException>(() => Subject.Get<HttpBinResource>(request));
+            var exception = Assert.ThrowsAsync<HttpException>(async () => await Subject.GetAsync<HttpBinResource>(request));
 
             ExceptionVerification.ExpectedWarns(1);
         }
@@ -264,28 +263,28 @@ namespace NzbDrone.Common.Test.Http
             var request = new HttpRequest($"https://{_httpBinHost}/status/{HttpStatusCode.NotFound}");
             request.LogHttpError = false;
 
-            var exception = Assert.Throws<HttpException>(() => Subject.Get<HttpBinResource>(request));
+            Assert.ThrowsAsync<HttpException>(async () => await Subject.GetAsync<HttpBinResource>(request));
 
             ExceptionVerification.ExpectedWarns(0);
         }
 
         [Test]
-        public void should_not_follow_redirects_when_not_in_production()
+        public async Task should_not_follow_redirects_when_not_in_production()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/redirect/1");
 
-            Subject.Get(request);
+            await Subject.GetAsync(request);
 
             ExceptionVerification.ExpectedErrors(1);
         }
 
         [Test]
-        public void should_follow_redirects()
+        public async Task should_follow_redirects()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/redirect/1");
             request.AllowAutoRedirect = true;
 
-            var response = Subject.Get(request);
+            var response = await Subject.GetAsync(request);
 
             response.StatusCode.Should().Be(HttpStatusCode.OK);
 
@@ -293,12 +292,12 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_not_follow_redirects()
+        public async Task should_not_follow_redirects()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/redirect/1");
             request.AllowAutoRedirect = false;
 
-            var response = Subject.Get(request);
+            var response = await Subject.GetAsync(request);
 
             response.StatusCode.Should().Be(HttpStatusCode.Found);
 
@@ -306,14 +305,14 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_follow_redirects_to_https()
+        public async Task should_follow_redirects_to_https()
         {
             var request = new HttpRequestBuilder($"https://{_httpBinHost}/redirect-to")
                 .AddQueryParam("url", $"https://readarr.com/")
                 .Build();
             request.AllowAutoRedirect = true;
 
-            var response = Subject.Get(request);
+            var response = await Subject.GetAsync(request);
 
             response.StatusCode.Should().Be(HttpStatusCode.OK);
             response.Content.Should().Contain("Readarr");
@@ -327,17 +326,17 @@ namespace NzbDrone.Common.Test.Http
             var request = new HttpRequest($"https://{_httpBinHost}/redirect/6");
             request.AllowAutoRedirect = true;
 
-            Assert.Throws<WebException>(() => Subject.Get(request));
+            Assert.ThrowsAsync<WebException>(async () => await Subject.GetAsync(request));
 
             ExceptionVerification.ExpectedErrors(0);
         }
 
         [Test]
-        public void should_send_user_agent()
+        public async Task should_send_user_agent()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/get");
 
-            var response = Subject.Get<HttpBinResource>(request);
+            var response = await Subject.GetAsync<HttpBinResource>(request);
 
             response.Resource.Headers.Should().ContainKey("User-Agent");
 
@@ -347,24 +346,24 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [TestCase("Accept", "text/xml, text/rss+xml, application/rss+xml")]
-        public void should_send_headers(string header, string value)
+        public async Task should_send_headers(string header, string value)
         {
             var request = new HttpRequest($"https://{_httpBinHost}/get");
             request.Headers.Add(header, value);
 
-            var response = Subject.Get<HttpBinResource>(request);
+            var response = await Subject.GetAsync<HttpBinResource>(request);
 
             response.Resource.Headers[header].ToString().Should().Be(value);
         }
 
         [Test]
-        public void should_download_file()
+        public async Task should_download_file()
         {
             var file = GetTempFilePath();
 
             var url = "https://readarr.com/img/slider/artistdetails.png";
 
-            Subject.DownloadFile(url, file);
+            await Subject.DownloadFileAsync(url, file);
 
             var fileInfo = new FileInfo(file);
             fileInfo.Exists.Should().BeTrue();
@@ -372,7 +371,7 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_download_file_with_redirect()
+        public async Task should_download_file_with_redirect()
         {
             var file = GetTempFilePath();
 
@@ -380,7 +379,7 @@ namespace NzbDrone.Common.Test.Http
                 .AddQueryParam("url", $"https://readarr.com/img/slider/artistdetails.png")
                 .Build();
 
-            Subject.DownloadFile(request.Url.FullUri, file);
+            await Subject.DownloadFileAsync(request.Url.FullUri, file);
 
             ExceptionVerification.ExpectedErrors(0);
 
@@ -394,7 +393,7 @@ namespace NzbDrone.Common.Test.Http
         {
             var file = GetTempFilePath();
 
-            Assert.Throws<HttpException>(() => Subject.DownloadFile("https://download.sonarr.tv/wrongpath", file));
+            Assert.ThrowsAsync<HttpException>(async () => await Subject.DownloadFileAsync("https://download.sonarr.tv/wrongpath", file));
 
             File.Exists(file).Should().BeFalse();
 
@@ -402,7 +401,7 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_not_write_redirect_content_to_stream()
+        public async Task should_not_write_redirect_content_to_stream()
         {
             var file = GetTempFilePath();
 
@@ -412,7 +411,7 @@ namespace NzbDrone.Common.Test.Http
                 request.AllowAutoRedirect = false;
                 request.ResponseStream = fileStream;
 
-                var response = Subject.Get(request);
+                var response = await Subject.GetAsync(request);
 
                 response.StatusCode.Should().Be(HttpStatusCode.Moved);
             }
@@ -427,12 +426,12 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_send_cookie()
+        public async Task should_send_cookie()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/get");
             request.Cookies["my"] = "cookie";
 
-            var response = Subject.Get<HttpBinResource>(request);
+            var response = await Subject.GetAsync<HttpBinResource>(request);
 
             response.Resource.Headers.Should().ContainKey("Cookie");
 
@@ -461,13 +460,13 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_preserve_cookie_during_session()
+        public async Task should_preserve_cookie_during_session()
         {
             GivenOldCookie();
 
             var request = new HttpRequest($"https://{_httpBinHost2}/get");
 
-            var response = Subject.Get<HttpBinResource>(request);
+            var response = await Subject.GetAsync<HttpBinResource>(request);
 
             response.Resource.Headers.Should().ContainKey("Cookie");
 
@@ -477,30 +476,30 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_not_send_cookie_to_other_host()
+        public async Task should_not_send_cookie_to_other_host()
         {
             GivenOldCookie();
 
             var request = new HttpRequest($"https://{_httpBinHost}/get");
 
-            var response = Subject.Get<HttpBinResource>(request);
+            var response = await Subject.GetAsync<HttpBinResource>(request);
 
             response.Resource.Headers.Should().NotContainKey("Cookie");
         }
 
         [Test]
-        public void should_not_store_request_cookie()
+        public async Task should_not_store_request_cookie()
         {
             var requestGet = new HttpRequest($"https://{_httpBinHost}/get");
             requestGet.Cookies.Add("my", "cookie");
             requestGet.AllowAutoRedirect = false;
             requestGet.StoreRequestCookie = false;
             requestGet.StoreResponseCookie = false;
-            var responseGet = Subject.Get<HttpBinResource>(requestGet);
+            var responseGet = await Subject.GetAsync<HttpBinResource>(requestGet);
 
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestCookies.AllowAutoRedirect = false;
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().BeEmpty();
 
@@ -508,18 +507,18 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_store_request_cookie()
+        public async Task should_store_request_cookie()
         {
             var requestGet = new HttpRequest($"https://{_httpBinHost}/get");
             requestGet.Cookies.Add("my", "cookie");
             requestGet.AllowAutoRedirect = false;
             requestGet.StoreRequestCookie.Should().BeTrue();
             requestGet.StoreResponseCookie = false;
-            var responseGet = Subject.Get<HttpBinResource>(requestGet);
+            var responseGet = await Subject.GetAsync<HttpBinResource>(requestGet);
 
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestCookies.AllowAutoRedirect = false;
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
 
@@ -527,7 +526,7 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_delete_request_cookie()
+        public async Task should_delete_request_cookie()
         {
             var requestDelete = new HttpRequest($"https://{_httpBinHost}/cookies/delete?my");
             requestDelete.Cookies.Add("my", "cookie");
@@ -536,13 +535,13 @@ namespace NzbDrone.Common.Test.Http
             requestDelete.StoreResponseCookie = false;
 
             // Delete and redirect since that's the only way to check the internal temporary cookie container
-            var responseCookies = Subject.Get<HttpCookieResource>(requestDelete);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestDelete);
 
             responseCookies.Resource.Cookies.Should().BeEmpty();
         }
 
         [Test]
-        public void should_clear_request_cookie()
+        public async Task should_clear_request_cookie()
         {
             var requestSet = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestSet.Cookies.Add("my", "cookie");
@@ -550,7 +549,7 @@ namespace NzbDrone.Common.Test.Http
             requestSet.StoreRequestCookie = true;
             requestSet.StoreResponseCookie = false;
 
-            var responseSet = Subject.Get<HttpCookieResource>(requestSet);
+            var responseSet = await Subject.GetAsync<HttpCookieResource>(requestSet);
 
             var requestClear = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestClear.Cookies.Add("my", null);
@@ -558,24 +557,24 @@ namespace NzbDrone.Common.Test.Http
             requestClear.StoreRequestCookie = true;
             requestClear.StoreResponseCookie = false;
 
-            var responseClear = Subject.Get<HttpCookieResource>(requestClear);
+            var responseClear = await Subject.GetAsync<HttpCookieResource>(requestClear);
 
             responseClear.Resource.Cookies.Should().BeEmpty();
         }
 
         [Test]
-        public void should_not_store_response_cookie()
+        public async Task should_not_store_response_cookie()
         {
             var requestSet = new HttpRequest($"https://{_httpBinHost}/cookies/set?my=cookie");
             requestSet.AllowAutoRedirect = false;
             requestSet.StoreRequestCookie = false;
             requestSet.StoreResponseCookie.Should().BeFalse();
 
-            var responseSet = Subject.Get(requestSet);
+            var responseSet = await Subject.GetAsync(requestSet);
 
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
 
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().BeEmpty();
 
@@ -583,18 +582,18 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_store_response_cookie()
+        public async Task should_store_response_cookie()
         {
             var requestSet = new HttpRequest($"https://{_httpBinHost}/cookies/set?my=cookie");
             requestSet.AllowAutoRedirect = false;
             requestSet.StoreRequestCookie = false;
             requestSet.StoreResponseCookie = true;
 
-            var responseSet = Subject.Get(requestSet);
+            var responseSet = await Subject.GetAsync(requestSet);
 
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
 
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
 
@@ -602,13 +601,13 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_temp_store_response_cookie()
+        public async Task should_temp_store_response_cookie()
         {
             var requestSet = new HttpRequest($"https://{_httpBinHost}/cookies/set?my=cookie");
             requestSet.AllowAutoRedirect = true;
             requestSet.StoreRequestCookie = false;
             requestSet.StoreResponseCookie.Should().BeFalse();
-            var responseSet = Subject.Get<HttpCookieResource>(requestSet);
+            var responseSet = await Subject.GetAsync<HttpCookieResource>(requestSet);
 
             // Set and redirect since that's the only way to check the internal temporary cookie container
             responseSet.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
@@ -617,7 +616,7 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_overwrite_response_cookie()
+        public async Task should_overwrite_response_cookie()
         {
             var requestSet = new HttpRequest($"https://{_httpBinHost}/cookies/set?my=cookie");
             requestSet.Cookies.Add("my", "oldcookie");
@@ -625,11 +624,11 @@ namespace NzbDrone.Common.Test.Http
             requestSet.StoreRequestCookie = false;
             requestSet.StoreResponseCookie = true;
 
-            var responseSet = Subject.Get(requestSet);
+            var responseSet = await Subject.GetAsync(requestSet);
 
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
 
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
 
@@ -637,7 +636,7 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_overwrite_temp_response_cookie()
+        public async Task should_overwrite_temp_response_cookie()
         {
             var requestSet = new HttpRequest($"https://{_httpBinHost}/cookies/set?my=cookie");
             requestSet.Cookies.Add("my", "oldcookie");
@@ -645,13 +644,13 @@ namespace NzbDrone.Common.Test.Http
             requestSet.StoreRequestCookie = true;
             requestSet.StoreResponseCookie = false;
 
-            var responseSet = Subject.Get<HttpCookieResource>(requestSet);
+            var responseSet = await Subject.GetAsync<HttpCookieResource>(requestSet);
 
             responseSet.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
 
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
 
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "oldcookie");
 
@@ -659,14 +658,14 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_not_delete_response_cookie()
+        public async Task should_not_delete_response_cookie()
         {
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestCookies.Cookies.Add("my", "cookie");
             requestCookies.AllowAutoRedirect = false;
             requestCookies.StoreRequestCookie = true;
             requestCookies.StoreResponseCookie = false;
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
 
@@ -675,13 +674,13 @@ namespace NzbDrone.Common.Test.Http
             requestDelete.StoreRequestCookie = false;
             requestDelete.StoreResponseCookie = false;
 
-            var responseDelete = Subject.Get(requestDelete);
+            var responseDelete = await Subject.GetAsync(requestDelete);
 
             requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestCookies.StoreRequestCookie = false;
             requestCookies.StoreResponseCookie = false;
 
-            responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
 
@@ -689,14 +688,14 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_delete_response_cookie()
+        public async Task should_delete_response_cookie()
         {
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestCookies.Cookies.Add("my", "cookie");
             requestCookies.AllowAutoRedirect = false;
             requestCookies.StoreRequestCookie = true;
             requestCookies.StoreResponseCookie = false;
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
 
@@ -705,13 +704,13 @@ namespace NzbDrone.Common.Test.Http
             requestDelete.StoreRequestCookie = false;
             requestDelete.StoreResponseCookie = true;
 
-            var responseDelete = Subject.Get(requestDelete);
+            var responseDelete = await Subject.GetAsync(requestDelete);
 
             requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestCookies.StoreRequestCookie = false;
             requestCookies.StoreResponseCookie = false;
 
-            responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().BeEmpty();
 
@@ -719,14 +718,14 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_delete_temp_response_cookie()
+        public async Task should_delete_temp_response_cookie()
         {
             var requestCookies = new HttpRequest($"https://{_httpBinHost}/cookies");
             requestCookies.Cookies.Add("my", "cookie");
             requestCookies.AllowAutoRedirect = false;
             requestCookies.StoreRequestCookie = true;
             requestCookies.StoreResponseCookie = false;
-            var responseCookies = Subject.Get<HttpCookieResource>(requestCookies);
+            var responseCookies = await Subject.GetAsync<HttpCookieResource>(requestCookies);
 
             responseCookies.Resource.Cookies.Should().HaveCount(1).And.Contain("my", "cookie");
 
@@ -734,7 +733,7 @@ namespace NzbDrone.Common.Test.Http
             requestDelete.AllowAutoRedirect = true;
             requestDelete.StoreRequestCookie = false;
             requestDelete.StoreResponseCookie = false;
-            var responseDelete = Subject.Get<HttpCookieResource>(requestDelete);
+            var responseDelete = await Subject.GetAsync<HttpCookieResource>(requestDelete);
 
             responseDelete.Resource.Cookies.Should().BeEmpty();
 
@@ -752,13 +751,13 @@ namespace NzbDrone.Common.Test.Http
         {
             var request = new HttpRequest($"https://{_httpBinHost}/status/429");
 
-            Assert.Throws<TooManyRequestsException>(() => Subject.Get(request));
+            Assert.ThrowsAsync<TooManyRequestsException>(async () => await Subject.GetAsync(request));
 
             ExceptionVerification.IgnoreWarns();
         }
 
         [Test]
-        public void should_call_interceptor()
+        public async Task should_call_interceptor()
         {
             Mocker.SetConstant<IEnumerable<IHttpRequestInterceptor>>(new[] { Mocker.GetMock<IHttpRequestInterceptor>().Object });
 
@@ -772,7 +771,7 @@ namespace NzbDrone.Common.Test.Http
 
             var request = new HttpRequest($"https://{_httpBinHost}/get");
 
-            Subject.Get(request);
+            await Subject.GetAsync(request);
 
             Mocker.GetMock<IHttpRequestInterceptor>()
                 .Verify(v => v.PreRequest(It.IsAny<HttpRequest>()), Times.Once());
@@ -783,7 +782,7 @@ namespace NzbDrone.Common.Test.Http
 
         [TestCase("en-US")]
         [TestCase("es-ES")]
-        public void should_parse_malformed_cloudflare_cookie(string culture)
+        public async Task should_parse_malformed_cloudflare_cookie(string culture)
         {
             var origCulture = Thread.CurrentThread.CurrentCulture;
             Thread.CurrentThread.CurrentCulture = CultureInfo.GetCultureInfo(culture);
@@ -799,11 +798,11 @@ namespace NzbDrone.Common.Test.Http
                 requestSet.AllowAutoRedirect = false;
                 requestSet.StoreResponseCookie = true;
 
-                var responseSet = Subject.Get(requestSet);
+                var responseSet = await Subject.GetAsync(requestSet);
 
                 var request = new HttpRequest($"https://{_httpBinHost}/get");
 
-                var response = Subject.Get<HttpBinResource>(request);
+                var response = await Subject.GetAsync<HttpBinResource>(request);
 
                 response.Resource.Headers.Should().ContainKey("Cookie");
 
@@ -821,7 +820,7 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [TestCase("lang_code=en; expires=Wed, 23-Dec-2026 18:09:14 GMT; Max-Age=31536000; path=/; domain=.abc.com")]
-        public void should_reject_malformed_domain_cookie(string malformedCookie)
+        public async Task should_reject_malformed_domain_cookie(string malformedCookie)
         {
             try
             {
@@ -831,11 +830,11 @@ namespace NzbDrone.Common.Test.Http
                 requestSet.AllowAutoRedirect = false;
                 requestSet.StoreResponseCookie = true;
 
-                var responseSet = Subject.Get(requestSet);
+                var responseSet = await Subject.GetAsync(requestSet);
 
                 var request = new HttpRequest($"https://{_httpBinHost}/get");
 
-                var response = Subject.Get<HttpBinResource>(request);
+                var response = await Subject.GetAsync<HttpBinResource>(request);
 
                 response.Resource.Headers.Should().NotContainKey("Cookie");
 
@@ -847,12 +846,12 @@ namespace NzbDrone.Common.Test.Http
         }
 
         [Test]
-        public void should_correctly_use_basic_auth_with_basic_network_credential()
+        public async Task should_correctly_use_basic_auth()
         {
             var request = new HttpRequest($"https://{_httpBinHost}/basic-auth/username/password");
             request.Credentials = new BasicNetworkCredential("username", "password");
 
-            var response = Subject.Execute(request);
+            var response = await Subject.ExecuteAsync(request);
 
             response.StatusCode.Should().Be(HttpStatusCode.OK);
         }
diff --git a/src/NzbDrone.Common/Http/Dispatchers/IHttpDispatcher.cs b/src/NzbDrone.Common/Http/Dispatchers/IHttpDispatcher.cs
index 8e665ceed..a5565f26b 100644
--- a/src/NzbDrone.Common/Http/Dispatchers/IHttpDispatcher.cs
+++ b/src/NzbDrone.Common/Http/Dispatchers/IHttpDispatcher.cs
@@ -1,9 +1,10 @@
 using System.Net;
+using System.Threading.Tasks;
 
 namespace NzbDrone.Common.Http.Dispatchers
 {
     public interface IHttpDispatcher
     {
-        HttpResponse GetResponse(HttpRequest request, CookieContainer cookies);
+        Task<HttpResponse> GetResponseAsync(HttpRequest request, CookieContainer cookies);
     }
 }
diff --git a/src/NzbDrone.Common/Http/Dispatchers/ManagedHttpDispatcher.cs b/src/NzbDrone.Common/Http/Dispatchers/ManagedHttpDispatcher.cs
index ad8cac315..812b85456 100644
--- a/src/NzbDrone.Common/Http/Dispatchers/ManagedHttpDispatcher.cs
+++ b/src/NzbDrone.Common/Http/Dispatchers/ManagedHttpDispatcher.cs
@@ -44,7 +44,7 @@ namespace NzbDrone.Common.Http.Dispatchers
             _credentialCache = cacheManager.GetCache<CredentialCache>(typeof(ManagedHttpDispatcher), "credentialcache");
         }
 
-        public HttpResponse GetResponse(HttpRequest request, CookieContainer cookies)
+        public async Task<HttpResponse> GetResponseAsync(HttpRequest request, CookieContainer cookies)
         {
             var requestMessage = new HttpRequestMessage(request.Method, (Uri)request.Url)
             {
@@ -103,7 +103,7 @@ namespace NzbDrone.Common.Http.Dispatchers
 
             var httpClient = GetClient(request.Url);
 
-            using var responseMessage = httpClient.Send(requestMessage, HttpCompletionOption.ResponseHeadersRead, cts.Token);
+            using var responseMessage = await httpClient.SendAsync(requestMessage, HttpCompletionOption.ResponseHeadersRead, cts.Token);
             {
                 byte[] data = null;
 
@@ -111,7 +111,7 @@ namespace NzbDrone.Common.Http.Dispatchers
                 {
                     if (request.ResponseStream != null && responseMessage.StatusCode == HttpStatusCode.OK)
                     {
-                        responseMessage.Content.CopyTo(request.ResponseStream, null, cts.Token);
+                        await responseMessage.Content.CopyToAsync(request.ResponseStream, null, cts.Token);
                     }
                     else
                     {
diff --git a/src/NzbDrone.Common/Http/HttpClient.cs b/src/NzbDrone.Common/Http/HttpClient.cs
index d65e1eba2..5b638ad3d 100644
--- a/src/NzbDrone.Common/Http/HttpClient.cs
+++ b/src/NzbDrone.Common/Http/HttpClient.cs
@@ -5,6 +5,7 @@ using System.IO;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
+using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.Cache;
 using NzbDrone.Common.EnvironmentInfo;
@@ -25,6 +26,16 @@ namespace NzbDrone.Common.Http
         HttpResponse Post(HttpRequest request);
         HttpResponse<T> Post<T>(HttpRequest request)
             where T : new();
+
+        Task<HttpResponse> ExecuteAsync(HttpRequest request);
+        Task DownloadFileAsync(string url, string fileName, string userAgent = null);
+        Task<HttpResponse> GetAsync(HttpRequest request);
+        Task<HttpResponse<T>> GetAsync<T>(HttpRequest request)
+            where T : new();
+        Task<HttpResponse> HeadAsync(HttpRequest request);
+        Task<HttpResponse> PostAsync(HttpRequest request);
+        Task<HttpResponse<T>> PostAsync<T>(HttpRequest request)
+            where T : new();
     }
 
     public class HttpClient : IHttpClient
@@ -52,11 +63,11 @@ namespace NzbDrone.Common.Http
             _cookieContainerCache = cacheManager.GetCache<CookieContainer>(typeof(HttpClient));
         }
 
-        public HttpResponse Execute(HttpRequest request)
+        public virtual async Task<HttpResponse> ExecuteAsync(HttpRequest request)
         {
             var cookieContainer = InitializeRequestCookies(request);
 
-            var response = ExecuteRequest(request, cookieContainer);
+            var response = await ExecuteRequestAsync(request, cookieContainer);
 
             if (request.AllowAutoRedirect && response.HasHttpRedirect)
             {
@@ -82,7 +93,7 @@ namespace NzbDrone.Common.Http
                         request.ContentSummary = null;
                     }
 
-                    response = ExecuteRequest(request, cookieContainer);
+                    response = await ExecuteRequestAsync(request, cookieContainer);
                 }
                 while (response.HasHttpRedirect);
             }
@@ -112,6 +123,11 @@ namespace NzbDrone.Common.Http
             return response;
         }
 
+        public HttpResponse Execute(HttpRequest request)
+        {
+            return ExecuteAsync(request).GetAwaiter().GetResult();
+        }
+
         private static bool RequestRequiresForceGet(HttpStatusCode statusCode, HttpMethod requestMethod)
         {
             return statusCode switch
@@ -122,7 +138,7 @@ namespace NzbDrone.Common.Http
             };
         }
 
-        private HttpResponse ExecuteRequest(HttpRequest request, CookieContainer cookieContainer)
+        private async Task<HttpResponse> ExecuteRequestAsync(HttpRequest request, CookieContainer cookieContainer)
         {
             foreach (var interceptor in _requestInterceptors)
             {
@@ -131,14 +147,14 @@ namespace NzbDrone.Common.Http
 
             if (request.RateLimit != TimeSpan.Zero)
             {
-                _rateLimitService.WaitAndPulse(request.Url.Host, request.RateLimitKey, request.RateLimit);
+                await _rateLimitService.WaitAndPulseAsync(request.Url.Host, request.RateLimitKey, request.RateLimit);
             }
 
             _logger.Trace(request);
 
             var stopWatch = Stopwatch.StartNew();
 
-            var response = _httpDispatcher.GetResponse(request, cookieContainer);
+            var response = await _httpDispatcher.GetResponseAsync(request, cookieContainer);
 
             HandleResponseCookies(response, cookieContainer);
 
@@ -246,7 +262,7 @@ namespace NzbDrone.Common.Http
             }
         }
 
-        public void DownloadFile(string url, string fileName, string userAgent = null)
+        public async Task DownloadFileAsync(string url, string fileName, string userAgent = null)
         {
             var fileNamePart = fileName + ".part";
 
@@ -261,12 +277,12 @@ namespace NzbDrone.Common.Http
                 _logger.Debug("Downloading [{0}] to [{1}]", url, fileName);
 
                 var stopWatch = Stopwatch.StartNew();
-                using (var fileStream = new FileStream(fileNamePart, FileMode.Create, FileAccess.ReadWrite))
+                await using (var fileStream = new FileStream(fileNamePart, FileMode.Create, FileAccess.ReadWrite))
                 {
                     var request = new HttpRequest(url);
                     request.AllowAutoRedirect = true;
                     request.ResponseStream = fileStream;
-                    var response = Get(request);
+                    var response = await GetAsync(request);
 
                     if (response.Headers.ContentType != null && response.Headers.ContentType.Contains("text/html"))
                     {
@@ -293,40 +309,73 @@ namespace NzbDrone.Common.Http
             }
         }
 
-        public HttpResponse Get(HttpRequest request)
+        public void DownloadFile(string url, string fileName, string userAgent = null)
+        {
+            // https://docs.microsoft.com/en-us/archive/msdn-magazine/2015/july/async-programming-brownfield-async-development#the-thread-pool-hack
+            Task.Run(() => DownloadFileAsync(url, fileName, userAgent)).GetAwaiter().GetResult();
+        }
+
+        public Task<HttpResponse> GetAsync(HttpRequest request)
         {
             request.Method = HttpMethod.Get;
-            return Execute(request);
+            return ExecuteAsync(request);
         }
 
-        public HttpResponse<T> Get<T>(HttpRequest request)
+        public HttpResponse Get(HttpRequest request)
+        {
+            return Task.Run(() => GetAsync(request)).GetAwaiter().GetResult();
+        }
+
+        public async Task<HttpResponse<T>> GetAsync<T>(HttpRequest request)
             where T : new()
         {
-            var response = Get(request);
+            var response = await GetAsync(request);
             CheckResponseContentType(response);
             return new HttpResponse<T>(response);
         }
 
-        public HttpResponse Head(HttpRequest request)
+        public HttpResponse<T> Get<T>(HttpRequest request)
+            where T : new()
+        {
+            return Task.Run(() => GetAsync<T>(request)).GetAwaiter().GetResult();
+        }
+
+        public Task<HttpResponse> HeadAsync(HttpRequest request)
         {
             request.Method = HttpMethod.Head;
-            return Execute(request);
+            return ExecuteAsync(request);
         }
 
-        public HttpResponse Post(HttpRequest request)
+        public HttpResponse Head(HttpRequest request)
+        {
+            return Task.Run(() => HeadAsync(request)).GetAwaiter().GetResult();
+        }
+
+        public Task<HttpResponse> PostAsync(HttpRequest request)
         {
             request.Method = HttpMethod.Post;
-            return Execute(request);
+            return ExecuteAsync(request);
         }
 
-        public HttpResponse<T> Post<T>(HttpRequest request)
+        public HttpResponse Post(HttpRequest request)
+        {
+            return Task.Run(() => PostAsync(request)).GetAwaiter().GetResult();
+        }
+
+        public async Task<HttpResponse<T>> PostAsync<T>(HttpRequest request)
             where T : new()
         {
-            var response = Post(request);
+            var response = await PostAsync(request);
             CheckResponseContentType(response);
             return new HttpResponse<T>(response);
         }
 
+        public HttpResponse<T> Post<T>(HttpRequest request)
+            where T : new()
+        {
+            return Task.Run(() => PostAsync<T>(request)).GetAwaiter().GetResult();
+        }
+
         private void CheckResponseContentType(HttpResponse response)
         {
             if (response.Headers.ContentType != null && response.Headers.ContentType.Contains("text/html"))
diff --git a/src/NzbDrone.Common/Http/HttpRequest.cs b/src/NzbDrone.Common/Http/HttpRequest.cs
index c9ef99f62..b3ce190d4 100644
--- a/src/NzbDrone.Common/Http/HttpRequest.cs
+++ b/src/NzbDrone.Common/Http/HttpRequest.cs
@@ -16,6 +16,7 @@ namespace NzbDrone.Common.Http
             Method = HttpMethod.Get;
             Url = new HttpUri(url);
             Headers = new HttpHeader();
+            ConnectionKeepAlive = true;
             AllowAutoRedirect = true;
             StoreRequestCookie = true;
             LogHttpError = true;
diff --git a/src/NzbDrone.Common/TPL/RateLimitService.cs b/src/NzbDrone.Common/TPL/RateLimitService.cs
index f006c378d..48de5db2e 100644
--- a/src/NzbDrone.Common/TPL/RateLimitService.cs
+++ b/src/NzbDrone.Common/TPL/RateLimitService.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Concurrent;
+using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.Cache;
 using NzbDrone.Common.Extensions;
@@ -10,6 +11,8 @@ namespace NzbDrone.Common.TPL
     {
         void WaitAndPulse(string key, TimeSpan interval);
         void WaitAndPulse(string key, string subKey, TimeSpan interval);
+        Task WaitAndPulseAsync(string key, TimeSpan interval);
+        Task WaitAndPulseAsync(string key, string subKey, TimeSpan interval);
     }
 
     public class RateLimitService : IRateLimitService
@@ -28,7 +31,34 @@ namespace NzbDrone.Common.TPL
             WaitAndPulse(key, null, interval);
         }
 
+        public async Task WaitAndPulseAsync(string key, TimeSpan interval)
+        {
+            await WaitAndPulseAsync(key, null, interval);
+        }
+
         public void WaitAndPulse(string key, string subKey, TimeSpan interval)
+        {
+            var delay = GetDelay(key, subKey, interval);
+
+            if (delay.TotalSeconds > 0.0)
+            {
+                _logger.Trace("Rate Limit triggered, delaying '{0}' for {1:0.000} sec", key, delay.TotalSeconds);
+                System.Threading.Thread.Sleep(delay);
+            }
+        }
+
+        public async Task WaitAndPulseAsync(string key, string subKey, TimeSpan interval)
+        {
+            var delay = GetDelay(key, subKey, interval);
+
+            if (delay.TotalSeconds > 0.0)
+            {
+                _logger.Trace("Rate Limit triggered, delaying '{0}' for {1:0.000} sec", key, delay.TotalSeconds);
+                await Task.Delay(delay);
+            }
+        }
+
+        private TimeSpan GetDelay(string key, string subKey, TimeSpan interval)
         {
             var waitUntil = DateTime.UtcNow.Add(interval);
 
@@ -59,13 +89,7 @@ namespace NzbDrone.Common.TPL
 
             waitUntil -= interval;
 
-            var delay = waitUntil - DateTime.UtcNow;
-
-            if (delay.TotalSeconds > 0.0)
-            {
-                _logger.Trace("Rate Limit triggered, delaying '{0}' for {1:0.000} sec", key, delay.TotalSeconds);
-                System.Threading.Thread.Sleep(delay);
-            }
+            return waitUntil - DateTime.UtcNow;
         }
     }
 }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadApprovedReportsTests/DownloadApprovedFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadApprovedReportsTests/DownloadApprovedFixture.cs
index e78ed6038..588e65c0f 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadApprovedReportsTests/DownloadApprovedFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadApprovedReportsTests/DownloadApprovedFixture.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using Moq;
@@ -58,7 +59,7 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
         }
 
         [Test]
-        public void should_download_report_if_book_was_not_already_downloaded()
+        public async Task should_download_report_if_book_was_not_already_downloaded()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -66,12 +67,12 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             var decisions = new List<DownloadDecision>();
             decisions.Add(new DownloadDecision(remoteBook));
 
-            Subject.ProcessDecisions(decisions);
+            await Subject.ProcessDecisions(decisions);
             Mocker.GetMock<IDownloadService>().Verify(v => v.DownloadReport(It.IsAny<RemoteBook>()), Times.Once());
         }
 
         [Test]
-        public void should_only_download_book_once()
+        public async Task should_only_download_book_once()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -80,12 +81,12 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             decisions.Add(new DownloadDecision(remoteBook));
             decisions.Add(new DownloadDecision(remoteBook));
 
-            Subject.ProcessDecisions(decisions);
+            await Subject.ProcessDecisions(decisions);
             Mocker.GetMock<IDownloadService>().Verify(v => v.DownloadReport(It.IsAny<RemoteBook>()), Times.Once());
         }
 
         [Test]
-        public void should_not_download_if_any_book_was_already_downloaded()
+        public async Task should_not_download_if_any_book_was_already_downloaded()
         {
             var remoteBook1 = GetRemoteBook(
                                                     new List<Book> { GetBook(1) },
@@ -99,12 +100,12 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             decisions.Add(new DownloadDecision(remoteBook1));
             decisions.Add(new DownloadDecision(remoteBook2));
 
-            Subject.ProcessDecisions(decisions);
+            await Subject.ProcessDecisions(decisions);
             Mocker.GetMock<IDownloadService>().Verify(v => v.DownloadReport(It.IsAny<RemoteBook>()), Times.Once());
         }
 
         [Test]
-        public void should_return_downloaded_reports()
+        public async Task should_return_downloaded_reports()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -112,11 +113,13 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             var decisions = new List<DownloadDecision>();
             decisions.Add(new DownloadDecision(remoteBook));
 
-            Subject.ProcessDecisions(decisions).Grabbed.Should().HaveCount(1);
+            var result = await Subject.ProcessDecisions(decisions);
+
+            result.Grabbed.Should().HaveCount(1);
         }
 
         [Test]
-        public void should_return_all_downloaded_reports()
+        public async Task should_return_all_downloaded_reports()
         {
             var remoteBook1 = GetRemoteBook(
                                                     new List<Book> { GetBook(1) },
@@ -130,11 +133,13 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             decisions.Add(new DownloadDecision(remoteBook1));
             decisions.Add(new DownloadDecision(remoteBook2));
 
-            Subject.ProcessDecisions(decisions).Grabbed.Should().HaveCount(2);
+            var result = await Subject.ProcessDecisions(decisions);
+
+            result.Grabbed.Should().HaveCount(2);
         }
 
         [Test]
-        public void should_only_return_downloaded_reports()
+        public async Task should_only_return_downloaded_reports()
         {
             var remoteBook1 = GetRemoteBook(
                                                     new List<Book> { GetBook(1) },
@@ -153,11 +158,13 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             decisions.Add(new DownloadDecision(remoteBook2));
             decisions.Add(new DownloadDecision(remoteBook3));
 
-            Subject.ProcessDecisions(decisions).Grabbed.Should().HaveCount(2);
+            var result = await Subject.ProcessDecisions(decisions);
+
+            result.Grabbed.Should().HaveCount(2);
         }
 
         [Test]
-        public void should_not_add_to_downloaded_list_when_download_fails()
+        public async Task should_not_add_to_downloaded_list_when_download_fails()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -166,7 +173,11 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             decisions.Add(new DownloadDecision(remoteBook));
 
             Mocker.GetMock<IDownloadService>().Setup(s => s.DownloadReport(It.IsAny<RemoteBook>())).Throws(new Exception());
-            Subject.ProcessDecisions(decisions).Grabbed.Should().BeEmpty();
+
+            var result = await Subject.ProcessDecisions(decisions);
+
+            result.Grabbed.Should().BeEmpty();
+
             ExceptionVerification.ExpectedWarns(1);
         }
 
@@ -181,7 +192,7 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
         }
 
         [Test]
-        public void should_not_grab_if_pending()
+        public async Task should_not_grab_if_pending()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -189,12 +200,12 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             var decisions = new List<DownloadDecision>();
             decisions.Add(new DownloadDecision(remoteBook, new Rejection("Failure!", RejectionType.Temporary)));
 
-            Subject.ProcessDecisions(decisions);
+            await Subject.ProcessDecisions(decisions);
             Mocker.GetMock<IDownloadService>().Verify(v => v.DownloadReport(It.IsAny<RemoteBook>()), Times.Never());
         }
 
         [Test]
-        public void should_not_add_to_pending_if_book_was_grabbed()
+        public async Task should_not_add_to_pending_if_book_was_grabbed()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -203,12 +214,12 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             decisions.Add(new DownloadDecision(remoteBook));
             decisions.Add(new DownloadDecision(remoteBook, new Rejection("Failure!", RejectionType.Temporary)));
 
-            Subject.ProcessDecisions(decisions);
+            await Subject.ProcessDecisions(decisions);
             Mocker.GetMock<IPendingReleaseService>().Verify(v => v.AddMany(It.IsAny<List<Tuple<DownloadDecision, PendingReleaseReason>>>()), Times.Never());
         }
 
         [Test]
-        public void should_add_to_pending_even_if_already_added_to_pending()
+        public async Task should_add_to_pending_even_if_already_added_to_pending()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -217,12 +228,12 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             decisions.Add(new DownloadDecision(remoteBook, new Rejection("Failure!", RejectionType.Temporary)));
             decisions.Add(new DownloadDecision(remoteBook, new Rejection("Failure!", RejectionType.Temporary)));
 
-            Subject.ProcessDecisions(decisions);
+            await Subject.ProcessDecisions(decisions);
             Mocker.GetMock<IPendingReleaseService>().Verify(v => v.AddMany(It.IsAny<List<Tuple<DownloadDecision, PendingReleaseReason>>>()), Times.Once());
         }
 
         [Test]
-        public void should_add_to_failed_if_already_failed_for_that_protocol()
+        public async Task should_add_to_failed_if_already_failed_for_that_protocol()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -234,12 +245,12 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             Mocker.GetMock<IDownloadService>().Setup(s => s.DownloadReport(It.IsAny<RemoteBook>()))
                   .Throws(new DownloadClientUnavailableException("Download client failed"));
 
-            Subject.ProcessDecisions(decisions);
+            await Subject.ProcessDecisions(decisions);
             Mocker.GetMock<IDownloadService>().Verify(v => v.DownloadReport(It.IsAny<RemoteBook>()), Times.Once());
         }
 
         [Test]
-        public void should_not_add_to_failed_if_failed_for_a_different_protocol()
+        public async Task should_not_add_to_failed_if_failed_for_a_different_protocol()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3), DownloadProtocol.Usenet);
@@ -252,13 +263,13 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
             Mocker.GetMock<IDownloadService>().Setup(s => s.DownloadReport(It.Is<RemoteBook>(r => r.Release.DownloadProtocol == DownloadProtocol.Usenet)))
                   .Throws(new DownloadClientUnavailableException("Download client failed"));
 
-            Subject.ProcessDecisions(decisions);
+            await Subject.ProcessDecisions(decisions);
             Mocker.GetMock<IDownloadService>().Verify(v => v.DownloadReport(It.Is<RemoteBook>(r => r.Release.DownloadProtocol == DownloadProtocol.Usenet)), Times.Once());
             Mocker.GetMock<IDownloadService>().Verify(v => v.DownloadReport(It.Is<RemoteBook>(r => r.Release.DownloadProtocol == DownloadProtocol.Torrent)), Times.Once());
         }
 
         [Test]
-        public void should_add_to_rejected_if_release_unavailable_on_indexer()
+        public async Task should_add_to_rejected_if_release_unavailable_on_indexer()
         {
             var books = new List<Book> { GetBook(1) };
             var remoteBook = GetRemoteBook(books, new QualityModel(Quality.MP3));
@@ -270,7 +281,7 @@ namespace NzbDrone.Core.Test.Download.DownloadApprovedReportsTests
                   .Setup(s => s.DownloadReport(It.IsAny<RemoteBook>()))
                   .Throws(new ReleaseUnavailableException(remoteBook.Release, "That 404 Error is not just a Quirk"));
 
-            var result = Subject.ProcessDecisions(decisions);
+            var result = await Subject.ProcessDecisions(decisions);
 
             result.Grabbed.Should().BeEmpty();
             result.Rejected.Should().NotBeEmpty();
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/Blackhole/TorrentBlackholeFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/Blackhole/TorrentBlackholeFixture.cs
index dc3db5e55..6a396c0bf 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/Blackhole/TorrentBlackholeFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/Blackhole/TorrentBlackholeFixture.cs
@@ -4,6 +4,7 @@ using System.IO;
 using System.IO.Abstractions;
 using System.Linq;
 using System.Net;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using Moq;
@@ -69,7 +70,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
         protected void GivenFailedDownload()
         {
             Mocker.GetMock<IHttpClient>()
-                .Setup(s => s.Get(It.IsAny<HttpRequest>()))
+                .Setup(s => s.GetAsync(It.IsAny<HttpRequest>()))
                 .Throws(new WebException());
         }
 
@@ -147,19 +148,19 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
         }
 
         [Test]
-        public void Download_should_download_file_if_it_doesnt_exist()
+        public async Task Download_should_download_file_if_it_doesnt_exist()
         {
             var remoteBook = CreateRemoteBook();
 
-            Subject.Download(remoteBook, CreateIndexer());
+            await Subject.Download(remoteBook, CreateIndexer());
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.Get(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.GetAsync(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_filePath), Times.Once());
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
         }
 
         [Test]
-        public void Download_should_save_magnet_if_enabled()
+        public async Task Download_should_save_magnet_if_enabled()
         {
             GivenMagnetFilePath();
             Subject.Definition.Settings.As<TorrentBlackholeSettings>().SaveMagnetFiles = true;
@@ -167,16 +168,16 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = null;
 
-            Subject.Download(remoteBook, CreateIndexer());
+            await Subject.Download(remoteBook, CreateIndexer());
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.Get(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.GetAsync(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Never());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_filePath), Times.Never());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_magnetFilePath), Times.Once());
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
         }
 
         [Test]
-        public void Download_should_save_magnet_using_specified_extension()
+        public async Task Download_should_save_magnet_using_specified_extension()
         {
             var magnetFileExtension = ".url";
             GivenMagnetFilePath(magnetFileExtension);
@@ -187,12 +188,12 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = null;
 
-            Subject.Download(remoteBook, CreateIndexer());
+            await Subject.Download(remoteBook, CreateIndexer());
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.Get(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.GetAsync(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Never());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_filePath), Times.Never());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_magnetFilePath), Times.Once());
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
         }
 
         [Test]
@@ -202,31 +203,31 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = null;
 
-            Assert.Throws<ReleaseDownloadException>(() => Subject.Download(remoteBook, CreateIndexer()));
+            Assert.ThrowsAsync<ReleaseDownloadException>(async () => await Subject.Download(remoteBook, CreateIndexer()));
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.Get(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.GetAsync(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Never());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_filePath), Times.Never());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_magnetFilePath), Times.Never());
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
         }
 
         [Test]
-        public void Download_should_prefer_torrent_over_magnet()
+        public async Task Download_should_prefer_torrent_over_magnet()
         {
             Subject.Definition.Settings.As<TorrentBlackholeSettings>().SaveMagnetFiles = true;
 
             var remoteBook = CreateRemoteBook();
 
-            Subject.Download(remoteBook, CreateIndexer());
+            await Subject.Download(remoteBook, CreateIndexer());
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.Get(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.GetAsync(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_filePath), Times.Once());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_magnetFilePath), Times.Never());
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
         }
 
         [Test]
-        public void Download_should_replace_illegal_characters_in_title()
+        public async Task Download_should_replace_illegal_characters_in_title()
         {
             var illegalTitle = "Radiohead - Scotch Mist [2008/FLAC/Lossless]";
             var expectedFilename = Path.Combine(_blackholeFolder, "Radiohead - Scotch Mist [2008+FLAC+Lossless]" + Path.GetExtension(_filePath));
@@ -234,11 +235,11 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.Title = illegalTitle;
 
-            Subject.Download(remoteBook, CreateIndexer());
+            await Subject.Download(remoteBook, CreateIndexer());
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.Get(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.GetAsync(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(expectedFilename), Times.Once());
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
         }
 
         [Test]
@@ -247,7 +248,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = null;
 
-            Assert.Throws<ReleaseDownloadException>(() => Subject.Download(remoteBook, CreateIndexer()));
+            Assert.ThrowsAsync<ReleaseDownloadException>(async () => await Subject.Download(remoteBook, CreateIndexer()));
         }
 
         [Test]
@@ -317,11 +318,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
         }
 
         [Test]
-        public void should_return_null_hash()
+        public async Task should_return_null_hash()
         {
             var remoteBook = CreateRemoteBook();
 
-            Subject.Download(remoteBook, CreateIndexer()).Should().BeNull();
+            var result = await Subject.Download(remoteBook, CreateIndexer());
+
+            result.Should().BeNull();
         }
     }
 }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/Blackhole/UsenetBlackholeFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/Blackhole/UsenetBlackholeFixture.cs
index f51cbe221..c2c202d59 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/Blackhole/UsenetBlackholeFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/Blackhole/UsenetBlackholeFixture.cs
@@ -4,6 +4,7 @@ using System.IO;
 using System.IO.Abstractions;
 using System.Linq;
 using System.Net;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using Moq;
@@ -119,19 +120,19 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
         }
 
         [Test]
-        public void Download_should_download_file_if_it_doesnt_exist()
+        public async Task Download_should_download_file_if_it_doesnt_exist()
         {
             var remoteBook = CreateRemoteBook();
 
-            Subject.Download(remoteBook, CreateIndexer());
+            await Subject.Download(remoteBook, CreateIndexer());
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.Get(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.GetAsync(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(_filePath), Times.Once());
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
         }
 
         [Test]
-        public void Download_should_replace_illegal_characters_in_title()
+        public async Task Download_should_replace_illegal_characters_in_title()
         {
             var illegalTitle = "Radiohead - Scotch Mist [2008/FLAC/Lossless]";
             var expectedFilename = Path.Combine(_blackholeFolder, "Radiohead - Scotch Mist [2008+FLAC+Lossless]" + Path.GetExtension(_filePath));
@@ -139,11 +140,11 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.Blackhole
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.Title = illegalTitle;
 
-            Subject.Download(remoteBook, CreateIndexer());
+            await Subject.Download(remoteBook, CreateIndexer());
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.Get(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.GetAsync(It.Is<HttpRequest>(v => v.Url.FullUri == _downloadUrl)), Times.Once());
             Mocker.GetMock<IDiskProvider>().Verify(c => c.OpenWriteStream(expectedFilename), Times.Once());
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never());
         }
 
         [Test]
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/DelugeTests/DelugeFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/DelugeTests/DelugeFixture.cs
index 2462ce677..086ed2dde 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/DelugeTests/DelugeFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/DelugeTests/DelugeFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -200,26 +201,26 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DelugeTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
 
         [TestCase("magnet:?xt=urn:btih:ZPBPA2P6ROZPKRHK44D5OW6NHXU5Z6KR&tr=udp", "CBC2F069FE8BB2F544EAE707D75BCD3DE9DCF951")]
-        public void Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
+        public async Task Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = magnetUrl;
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().Be(expectedHash);
         }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadClientFixtureBase.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadClientFixtureBase.cs
index 14aeb8c4b..f2960c0d5 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadClientFixtureBase.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadClientFixtureBase.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NLog;
@@ -36,8 +37,8 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests
                 .Returns(() => CreateRemoteBook());
 
             Mocker.GetMock<IHttpClient>()
-                  .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Setup(s => s.GetAsync(It.IsAny<HttpRequest>()))
+                  .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), Array.Empty<byte>())));
 
             Mocker.GetMock<IRemotePathMappingService>()
                 .Setup(v => v.RemapRemoteToLocal(It.IsAny<string>(), It.IsAny<OsPath>()))
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/TorrentDownloadStationFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/TorrentDownloadStationFixture.cs
index 2a770587f..d39fda2b8 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/TorrentDownloadStationFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/TorrentDownloadStationFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -385,7 +386,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
         }
 
         [Test]
-        public void Download_with_TvDirectory_should_force_directory()
+        public async Task Download_with_TvDirectory_should_force_directory()
         {
             GivenSerialNumber();
             GivenTvDirectory();
@@ -393,7 +394,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -402,7 +403,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
         }
 
         [Test]
-        public void Download_with_category_should_force_directory()
+        public async Task Download_with_category_should_force_directory()
         {
             GivenSerialNumber();
             GivenMusicCategory();
@@ -410,7 +411,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -419,14 +420,14 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
         }
 
         [Test]
-        public void Download_without_TvDirectory_and_Category_should_use_default()
+        public async Task Download_without_TvDirectory_and_Category_should_use_default()
         {
             GivenSerialNumber();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -505,7 +506,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
                   .Setup(s => s.GetSerialNumber(_settings))
                   .Throws(new ApplicationException("Some unknown exception, HttpException or DownloadClientException"));
 
-            Assert.Throws(Is.InstanceOf<Exception>(), () => Subject.Download(remoteBook, CreateIndexer()));
+            Assert.ThrowsAsync(Is.InstanceOf<Exception>(), async () => await Subject.Download(remoteBook, CreateIndexer()));
 
             Mocker.GetMock<IDownloadStationTaskProxy>()
                   .Verify(v => v.AddTaskFromUrl(It.IsAny<string>(), null, _settings), Times.Never());
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/UsenetDownloadStationFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/UsenetDownloadStationFixture.cs
index eeb90c490..328021733 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/UsenetDownloadStationFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/UsenetDownloadStationFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -262,7 +263,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
         }
 
         [Test]
-        public void Download_with_TvDirectory_should_force_directory()
+        public async Task Download_with_TvDirectory_should_force_directory()
         {
             GivenSerialNumber();
             GivenTvDirectory();
@@ -270,7 +271,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -279,7 +280,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
         }
 
         [Test]
-        public void Download_with_category_should_force_directory()
+        public async Task Download_with_category_should_force_directory()
         {
             GivenSerialNumber();
             GivenMusicCategory();
@@ -287,7 +288,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -296,14 +297,14 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
         }
 
         [Test]
-        public void Download_without_TvDirectory_and_Category_should_use_default()
+        public async Task Download_without_TvDirectory_and_Category_should_use_default()
         {
             GivenSerialNumber();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -382,7 +383,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
                   .Setup(s => s.GetSerialNumber(_settings))
                   .Throws(new ApplicationException("Some unknown exception, HttpException or DownloadClientException"));
 
-            Assert.Throws(Is.InstanceOf<Exception>(), () => Subject.Download(remoteBook, CreateIndexer()));
+            Assert.ThrowsAsync(Is.InstanceOf<Exception>(), async () => await Subject.Download(remoteBook, CreateIndexer()));
 
             Mocker.GetMock<IDownloadStationTaskProxy>()
                   .Verify(v => v.AddTaskFromUrl(It.IsAny<string>(), null, _settings), Times.Never());
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/HadoukenTests/HadoukenFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/HadoukenTests/HadoukenFixture.cs
index d7495059e..f012575ce 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/HadoukenTests/HadoukenFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/HadoukenTests/HadoukenFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -103,8 +104,8 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.HadoukenTests
         protected void GivenSuccessfulDownload()
         {
             Mocker.GetMock<IHttpClient>()
-                  .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[1000]));
+                  .Setup(s => s.GetAsync(It.IsAny<HttpRequest>()))
+                  .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), new byte[1000])));
 
             Mocker.GetMock<IHadoukenProxy>()
                 .Setup(s => s.AddTorrentUri(It.IsAny<HadoukenSettings>(), It.IsAny<string>()))
@@ -196,13 +197,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.HadoukenTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
@@ -277,7 +278,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.HadoukenTests
         }
 
         [Test]
-        public void Download_from_magnet_link_should_return_hash_uppercase()
+        public async Task Download_from_magnet_link_should_return_hash_uppercase()
         {
             var remoteBook = CreateRemoteBook();
 
@@ -286,13 +287,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.HadoukenTests
             Mocker.GetMock<IHadoukenProxy>()
                .Setup(v => v.AddTorrentUri(It.IsAny<HadoukenSettings>(), It.IsAny<string>()));
 
-            var result = Subject.Download(remoteBook, CreateIndexer());
+            var result = await Subject.Download(remoteBook, CreateIndexer());
 
             Assert.IsFalse(result.Any(c => char.IsLower(c)));
         }
 
         [Test]
-        public void Download_from_torrent_file_should_return_hash_uppercase()
+        public async Task Download_from_torrent_file_should_return_hash_uppercase()
         {
             var remoteBook = CreateRemoteBook();
 
@@ -300,7 +301,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.HadoukenTests
                .Setup(v => v.AddTorrentFile(It.IsAny<HadoukenSettings>(), It.IsAny<byte[]>()))
                .Returns("hash");
 
-            var result = Subject.Download(remoteBook, CreateIndexer());
+            var result = await Subject.Download(remoteBook, CreateIndexer());
 
             Assert.IsFalse(result.Any(c => char.IsLower(c)));
         }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/NzbVortexTests/NzbVortexFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/NzbVortexTests/NzbVortexFixture.cs
index 971c947b2..a0c46e382 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/NzbVortexTests/NzbVortexFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/NzbVortexTests/NzbVortexFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -200,13 +201,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.NzbVortexTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
@@ -218,7 +219,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.NzbVortexTests
 
             var remoteBook = CreateRemoteBook();
 
-            Assert.Throws<DownloadClientException>(() => Subject.Download(remoteBook, CreateIndexer()));
+            Assert.ThrowsAsync<DownloadClientException>(async () => await Subject.Download(remoteBook, CreateIndexer()));
         }
 
         [Test]
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/NzbgetTests/NzbgetFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/NzbgetTests/NzbgetFixture.cs
index 1e7115f63..ea4c100ff 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/NzbgetTests/NzbgetFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/NzbgetTests/NzbgetFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using Moq;
@@ -339,13 +340,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.NzbgetTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
@@ -357,7 +358,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.NzbgetTests
 
             var remoteBook = CreateRemoteBook();
 
-            Assert.Throws<DownloadClientRejectedReleaseException>(() => Subject.Download(remoteBook, CreateIndexer()));
+            Assert.ThrowsAsync<DownloadClientRejectedReleaseException>(async () => await Subject.Download(remoteBook, CreateIndexer()));
         }
 
         [Test]
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/PneumaticProviderFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/PneumaticProviderFixture.cs
index 74dfdae29..6202f4a85 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/PneumaticProviderFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/PneumaticProviderFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Net;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using Moq;
 using NLog;
@@ -65,15 +66,15 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests
 
         private void WithFailedDownload()
         {
-            Mocker.GetMock<IHttpClient>().Setup(c => c.DownloadFile(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>())).Throws(new WebException());
+            Mocker.GetMock<IHttpClient>().Setup(c => c.DownloadFileAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>())).Throws(new WebException());
         }
 
         [Test]
-        public void should_download_file_if_it_doesnt_exist()
+        public async Task should_download_file_if_it_doesnt_exist()
         {
-            Subject.Download(_remoteBook, _indexer);
+            await Subject.Download(_remoteBook, _indexer);
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(_nzbUrl, _nzbPath, null), Times.Once());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(_nzbUrl, _nzbPath, null), Times.Once());
         }
 
         [Test]
@@ -81,7 +82,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests
         {
             WithFailedDownload();
 
-            Assert.Throws<WebException>(() => Subject.Download(_remoteBook, _indexer));
+            Assert.ThrowsAsync<WebException>(async () => await Subject.Download(_remoteBook, _indexer));
         }
 
         [Test]
@@ -90,7 +91,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests
             _remoteBook.Release.Title = "Alien Ant Farm - Discography";
             _remoteBook.ParsedBookInfo.Discography = true;
 
-            Assert.Throws<NotSupportedException>(() => Subject.Download(_remoteBook, _indexer));
+            Assert.ThrowsAsync<NotSupportedException>(async () => await Subject.Download(_remoteBook, _indexer));
         }
 
         [Test]
@@ -100,15 +101,15 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests
         }
 
         [Test]
-        public void should_replace_illegal_characters_in_title()
+        public async Task should_replace_illegal_characters_in_title()
         {
             var illegalTitle = "Saturday Night Live - S38E08 - Jeremy Renner/Maroon 5 [SDTV]";
             var expectedFilename = Path.Combine(_pneumaticFolder, "Saturday Night Live - S38E08 - Jeremy Renner+Maroon 5 [SDTV].nzb");
             _remoteBook.Release.Title = illegalTitle;
 
-            Subject.Download(_remoteBook, _indexer);
+            await Subject.Download(_remoteBook, _indexer);
 
-            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFile(It.IsAny<string>(), expectedFilename, null), Times.Once());
+            Mocker.GetMock<IHttpClient>().Verify(c => c.DownloadFileAsync(It.IsAny<string>(), expectedFilename, null), Times.Once());
         }
     }
 }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/QBittorrentTests/QBittorrentFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/QBittorrentTests/QBittorrentFixture.cs
index 2c123b173..17a7518e2 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/QBittorrentTests/QBittorrentFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/QBittorrentTests/QBittorrentFixture.cs
@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -449,26 +450,26 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
 
         [TestCase("magnet:?xt=urn:btih:ZPBPA2P6ROZPKRHK44D5OW6NHXU5Z6KR&tr=udp", "CBC2F069FE8BB2F544EAE707D75BCD3DE9DCF951")]
-        public void Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
+        public async Task Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = magnetUrl;
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().Be(expectedHash);
         }
@@ -483,7 +484,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = "magnet:?xt=urn:btih:ZPBPA2P6ROZPKRHK44D5OW6NHXU5Z6KR";
 
-            Assert.Throws<ReleaseDownloadException>(() => Subject.Download(remoteBook, CreateIndexer()));
+            Assert.ThrowsAsync<ReleaseDownloadException>(async () => await Subject.Download(remoteBook, CreateIndexer()));
         }
 
         [Test]
@@ -496,28 +497,28 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = "magnet:?xt=urn:btih:ZPBPA2P6ROZPKRHK44D5OW6NHXU5Z6KR&tr=udp://abc";
 
-            Assert.DoesNotThrow(() => Subject.Download(remoteBook, CreateIndexer()));
+            Assert.DoesNotThrowAsync(async () => await Subject.Download(remoteBook, CreateIndexer()));
 
             Mocker.GetMock<IQBittorrentProxy>()
                   .Verify(s => s.AddTorrentFromUrl(It.IsAny<string>(), It.IsAny<TorrentSeedConfiguration>(), It.IsAny<QBittorrentSettings>()), Times.Once());
         }
 
         [Test]
-        public void Download_should_set_top_priority()
+        public async Task Download_should_set_top_priority()
         {
             GivenHighPriority();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             Mocker.GetMock<IQBittorrentProxy>()
                   .Verify(v => v.MoveTorrentToTopInQueue(It.IsAny<string>(), It.IsAny<QBittorrentSettings>()), Times.Once());
         }
 
         [Test]
-        public void Download_should_not_fail_if_top_priority_not_available()
+        public async Task Download_should_not_fail_if_top_priority_not_available()
         {
             GivenHighPriority();
             GivenSuccessfulDownload();
@@ -528,7 +529,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -555,27 +556,27 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
         }
 
         [Test]
-        public void Download_should_handle_http_redirect_to_magnet()
+        public async Task Download_should_handle_http_redirect_to_magnet()
         {
             GivenRedirectToMagnet();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
 
         [Test]
-        public void Download_should_handle_http_redirect_to_torrent()
+        public async Task Download_should_handle_http_redirect_to_torrent()
         {
             GivenRedirectToTorrent();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/RTorrentTests/RTorrentFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/RTorrentTests/RTorrentFixture.cs
index 4a3d12efe..fd2481150 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/RTorrentTests/RTorrentFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/RTorrentTests/RTorrentFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -121,13 +122,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.RTorrentTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/SabnzbdTests/SabnzbdFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/SabnzbdTests/SabnzbdFixture.cs
index 2927eddef..bbd803034 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/SabnzbdTests/SabnzbdFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/SabnzbdTests/SabnzbdFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using Moq;
@@ -300,27 +301,27 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.SabnzbdTests
         }
 
         [TestCase("[ TOWN ]-[ http://www.town.ag ]-[ ANIME ]-[Usenet Provider >> http://www.ssl- <<] - [Commie] Aldnoah Zero 18 [234C8FC7]", "[ TOWN ]-[ http-++www.town.ag ]-[ ANIME ]-[Usenet Provider  http-++www.ssl- ] - [Commie] Aldnoah Zero 18 [234C8FC7].nzb")]
-        public void Download_should_use_clean_title(string title, string filename)
+        public async Task Download_should_use_clean_title(string title, string filename)
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.Title = title;
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             Mocker.GetMock<ISabnzbdProxy>()
                 .Verify(v => v.DownloadNzb(It.IsAny<byte[]>(), filename, It.IsAny<string>(), It.IsAny<int>(), It.IsAny<SabnzbdSettings>()), Times.Once());
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
@@ -353,7 +354,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.SabnzbdTests
         }
 
         [Test]
-        public void Download_should_use_sabRecentTvPriority_when_recentEpisode_is_true()
+        public async Task Download_should_use_sabRecentTvPriority_when_recentEpisode_is_true()
         {
             Mocker.GetMock<ISabnzbdProxy>()
                     .Setup(s => s.DownloadNzb(It.IsAny<byte[]>(), It.IsAny<string>(), It.IsAny<string>(), (int)SabnzbdPriority.High, It.IsAny<SabnzbdSettings>()))
@@ -366,7 +367,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.SabnzbdTests
                                                       .Build()
                                                       .ToList();
 
-            Subject.Download(remoteBook, CreateIndexer());
+            await Subject.Download(remoteBook, CreateIndexer());
 
             Mocker.GetMock<ISabnzbdProxy>()
                   .Verify(v => v.DownloadNzb(It.IsAny<byte[]>(), It.IsAny<string>(), It.IsAny<string>(), (int)SabnzbdPriority.High, It.IsAny<SabnzbdSettings>()), Times.Once());
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/TransmissionTests/TransmissionFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/TransmissionTests/TransmissionFixture.cs
index 52eed5614..1d66ff7f3 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/TransmissionTests/TransmissionFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/TransmissionTests/TransmissionFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -55,26 +56,26 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.TransmissionTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
 
         [Test]
-        public void Download_with_TvDirectory_should_force_directory()
+        public async Task Download_with_TvDirectory_should_force_directory()
         {
             GivenTvDirectory();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -83,14 +84,14 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.TransmissionTests
         }
 
         [Test]
-        public void Download_with_category_should_force_directory()
+        public async Task Download_with_category_should_force_directory()
         {
             GivenMusicCategory();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -99,7 +100,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.TransmissionTests
         }
 
         [Test]
-        public void Download_with_category_should_not_have_double_slashes()
+        public async Task Download_with_category_should_not_have_double_slashes()
         {
             GivenMusicCategory();
             GivenSuccessfulDownload();
@@ -108,7 +109,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.TransmissionTests
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -117,13 +118,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.TransmissionTests
         }
 
         [Test]
-        public void Download_without_TvDirectory_and_Category_should_use_default()
+        public async Task Download_without_TvDirectory_and_Category_should_use_default()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -132,14 +133,14 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.TransmissionTests
         }
 
         [TestCase("magnet:?xt=urn:btih:ZPBPA2P6ROZPKRHK44D5OW6NHXU5Z6KR&tr=udp", "CBC2F069FE8BB2F544EAE707D75BCD3DE9DCF951")]
-        public void Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
+        public async Task Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = magnetUrl;
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().Be(expectedHash);
         }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/UTorrentTests/UTorrentFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/UTorrentTests/UTorrentFixture.cs
index 8aced935a..23384b78e 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/UTorrentTests/UTorrentFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/UTorrentTests/UTorrentFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -228,13 +229,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.UTorrentTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
@@ -252,14 +253,14 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.UTorrentTests
 
         // Proxy.GetTorrents does not return original url. So item has to be found via magnet url.
         [TestCase("magnet:?xt=urn:btih:ZPBPA2P6ROZPKRHK44D5OW6NHXU5Z6KR&tr=udp", "CBC2F069FE8BB2F544EAE707D75BCD3DE9DCF951")]
-        public void Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
+        public async Task Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = magnetUrl;
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().Be(expectedHash);
         }
@@ -350,27 +351,27 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.UTorrentTests
         }
 
         [Test]
-        public void Download_should_handle_http_redirect_to_magnet()
+        public async Task Download_should_handle_http_redirect_to_magnet()
         {
             GivenRedirectToMagnet();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
 
         [Test]
-        public void Download_should_handle_http_redirect_to_torrent()
+        public async Task Download_should_handle_http_redirect_to_torrent()
         {
             GivenRedirectToTorrent();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadClientTests/VuzeTests/VuzeFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadClientTests/VuzeTests/VuzeFixture.cs
index 9a507ae34..1229c72ff 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadClientTests/VuzeTests/VuzeFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadClientTests/VuzeTests/VuzeFixture.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -63,26 +64,26 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.VuzeTests
         }
 
         [Test]
-        public void Download_should_return_unique_id()
+        public async Task Download_should_return_unique_id()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
         }
 
         [Test]
-        public void Download_with_TvDirectory_should_force_directory()
+        public async Task Download_with_TvDirectory_should_force_directory()
         {
             GivenTvDirectory();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -91,14 +92,14 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.VuzeTests
         }
 
         [Test]
-        public void Download_with_category_should_force_directory()
+        public async Task Download_with_category_should_force_directory()
         {
             GivenMusicCategory();
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -107,7 +108,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.VuzeTests
         }
 
         [Test]
-        public void Download_with_category_should_not_have_double_slashes()
+        public async Task Download_with_category_should_not_have_double_slashes()
         {
             GivenMusicCategory();
             GivenSuccessfulDownload();
@@ -116,7 +117,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.VuzeTests
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -125,13 +126,13 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.VuzeTests
         }
 
         [Test]
-        public void Download_without_TvDirectory_and_Category_should_use_default()
+        public async Task Download_without_TvDirectory_and_Category_should_use_default()
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().NotBeNullOrEmpty();
 
@@ -140,14 +141,14 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.VuzeTests
         }
 
         [TestCase("magnet:?xt=urn:btih:ZPBPA2P6ROZPKRHK44D5OW6NHXU5Z6KR&tr=udp", "CBC2F069FE8BB2F544EAE707D75BCD3DE9DCF951")]
-        public void Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
+        public async Task Download_should_get_hash_from_magnet_url(string magnetUrl, string expectedHash)
         {
             GivenSuccessfulDownload();
 
             var remoteBook = CreateRemoteBook();
             remoteBook.Release.DownloadUrl = magnetUrl;
 
-            var id = Subject.Download(remoteBook, CreateIndexer());
+            var id = await Subject.Download(remoteBook, CreateIndexer());
 
             id.Should().Be(expectedHash);
         }
diff --git a/src/NzbDrone.Core.Test/Download/DownloadServiceFixture.cs b/src/NzbDrone.Core.Test/Download/DownloadServiceFixture.cs
index 0ea296c9f..39af065f1 100644
--- a/src/NzbDrone.Core.Test/Download/DownloadServiceFixture.cs
+++ b/src/NzbDrone.Core.Test/Download/DownloadServiceFixture.cs
@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Net;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using Moq;
 using NUnit.Framework;
@@ -77,23 +78,23 @@ namespace NzbDrone.Core.Test.Download
         }
 
         [Test]
-        public void Download_report_should_publish_on_grab_event()
+        public async Task Download_report_should_publish_on_grab_event()
         {
             var mock = WithUsenetClient();
             mock.Setup(s => s.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()));
 
-            Subject.DownloadReport(_parseResult);
+            await Subject.DownloadReport(_parseResult);
 
             VerifyEventPublished<BookGrabbedEvent>();
         }
 
         [Test]
-        public void Download_report_should_grab_using_client()
+        public async Task Download_report_should_grab_using_client()
         {
             var mock = WithUsenetClient();
             mock.Setup(s => s.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()));
 
-            Subject.DownloadReport(_parseResult);
+            await Subject.DownloadReport(_parseResult);
 
             mock.Verify(s => s.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()), Times.Once());
         }
@@ -105,7 +106,7 @@ namespace NzbDrone.Core.Test.Download
             mock.Setup(s => s.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()))
                 .Throws(new WebException());
 
-            Assert.Throws<WebException>(() => Subject.DownloadReport(_parseResult));
+            Assert.ThrowsAsync<WebException>(async () => await Subject.DownloadReport(_parseResult));
 
             VerifyEventNotPublished<BookGrabbedEvent>();
         }
@@ -120,7 +121,7 @@ namespace NzbDrone.Core.Test.Download
                     throw new ReleaseDownloadException(v.Release, "Error", new WebException());
                 });
 
-            Assert.Throws<ReleaseDownloadException>(() => Subject.DownloadReport(_parseResult));
+            Assert.ThrowsAsync<ReleaseDownloadException>(async () => await Subject.DownloadReport(_parseResult));
 
             Mocker.GetMock<IIndexerStatusService>()
                 .Verify(v => v.RecordFailure(It.IsAny<int>(), It.IsAny<TimeSpan>()), Times.Once());
@@ -140,7 +141,7 @@ namespace NzbDrone.Core.Test.Download
                     throw new ReleaseDownloadException(v.Release, "Error", new TooManyRequestsException(request, response));
                 });
 
-            Assert.Throws<ReleaseDownloadException>(() => Subject.DownloadReport(_parseResult));
+            Assert.ThrowsAsync<ReleaseDownloadException>(async () => await Subject.DownloadReport(_parseResult));
 
             Mocker.GetMock<IIndexerStatusService>()
                 .Verify(v => v.RecordFailure(It.IsAny<int>(), TimeSpan.FromMinutes(5.0)), Times.Once());
@@ -160,7 +161,7 @@ namespace NzbDrone.Core.Test.Download
                     throw new ReleaseDownloadException(v.Release, "Error", new TooManyRequestsException(request, response));
                 });
 
-            Assert.Throws<ReleaseDownloadException>(() => Subject.DownloadReport(_parseResult));
+            Assert.ThrowsAsync<ReleaseDownloadException>(async () => await Subject.DownloadReport(_parseResult));
 
             Mocker.GetMock<IIndexerStatusService>()
                 .Verify(v => v.RecordFailure(It.IsAny<int>(),
@@ -174,7 +175,7 @@ namespace NzbDrone.Core.Test.Download
             mock.Setup(s => s.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()))
                 .Throws(new DownloadClientException("Some Error"));
 
-            Assert.Throws<DownloadClientException>(() => Subject.DownloadReport(_parseResult));
+            Assert.ThrowsAsync<DownloadClientException>(async () => await Subject.DownloadReport(_parseResult));
 
             Mocker.GetMock<IIndexerStatusService>()
                 .Verify(v => v.RecordFailure(It.IsAny<int>(), It.IsAny<TimeSpan>()), Times.Never());
@@ -190,7 +191,7 @@ namespace NzbDrone.Core.Test.Download
                     throw new ReleaseUnavailableException(v.Release, "Error", new WebException());
                 });
 
-            Assert.Throws<ReleaseUnavailableException>(() => Subject.DownloadReport(_parseResult));
+            Assert.ThrowsAsync<ReleaseUnavailableException>(async () => await Subject.DownloadReport(_parseResult));
 
             Mocker.GetMock<IIndexerStatusService>()
                 .Verify(v => v.RecordFailure(It.IsAny<int>(), It.IsAny<TimeSpan>()), Times.Never());
@@ -199,14 +200,14 @@ namespace NzbDrone.Core.Test.Download
         [Test]
         public void should_not_attempt_download_if_client_isnt_configured()
         {
-            Assert.Throws<DownloadClientUnavailableException>(() => Subject.DownloadReport(_parseResult));
+            Assert.ThrowsAsync<DownloadClientUnavailableException>(async () => await Subject.DownloadReport(_parseResult));
 
             Mocker.GetMock<IDownloadClient>().Verify(c => c.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()), Times.Never());
             VerifyEventNotPublished<BookGrabbedEvent>();
         }
 
         [Test]
-        public void should_attempt_download_even_if_client_is_disabled()
+        public async Task should_attempt_download_even_if_client_is_disabled()
         {
             var mockUsenet = WithUsenetClient();
 
@@ -221,7 +222,7 @@ namespace NzbDrone.Core.Test.Download
                         }
                     });
 
-            Subject.DownloadReport(_parseResult);
+            await Subject.DownloadReport(_parseResult);
 
             Mocker.GetMock<IDownloadClientStatusService>().Verify(c => c.GetBlockedProviders(), Times.Never());
             mockUsenet.Verify(c => c.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()), Times.Once());
@@ -229,26 +230,26 @@ namespace NzbDrone.Core.Test.Download
         }
 
         [Test]
-        public void should_send_download_to_correct_usenet_client()
+        public async Task should_send_download_to_correct_usenet_client()
         {
             var mockTorrent = WithTorrentClient();
             var mockUsenet = WithUsenetClient();
 
-            Subject.DownloadReport(_parseResult);
+            await Subject.DownloadReport(_parseResult);
 
             mockTorrent.Verify(c => c.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()), Times.Never());
             mockUsenet.Verify(c => c.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()), Times.Once());
         }
 
         [Test]
-        public void should_send_download_to_correct_torrent_client()
+        public async Task should_send_download_to_correct_torrent_client()
         {
             var mockTorrent = WithTorrentClient();
             var mockUsenet = WithUsenetClient();
 
             _parseResult.Release.DownloadProtocol = DownloadProtocol.Torrent;
 
-            Subject.DownloadReport(_parseResult);
+            await Subject.DownloadReport(_parseResult);
 
             mockTorrent.Verify(c => c.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()), Times.Once());
             mockUsenet.Verify(c => c.Download(It.IsAny<RemoteBook>(), It.IsAny<IIndexer>()), Times.Never());
diff --git a/src/NzbDrone.Core.Test/IndexerSearchTests/AuthorSearchServiceFixture.cs b/src/NzbDrone.Core.Test/IndexerSearchTests/AuthorSearchServiceFixture.cs
index 73f01a6af..1f524fcf8 100644
--- a/src/NzbDrone.Core.Test/IndexerSearchTests/AuthorSearchServiceFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerSearchTests/AuthorSearchServiceFixture.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using Moq;
 using NUnit.Framework;
 using NzbDrone.Core.Books;
@@ -27,11 +28,11 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
 
             Mocker.GetMock<ISearchForReleases>()
                 .Setup(s => s.AuthorSearch(_author.Id, false, true, false))
-                .Returns(new List<DownloadDecision>());
+                .Returns(Task.FromResult(new List<DownloadDecision>()));
 
             Mocker.GetMock<IProcessDownloadDecisions>()
                 .Setup(s => s.ProcessDecisions(It.IsAny<List<DownloadDecision>>()))
-                .Returns(new ProcessedDecisions(new List<DownloadDecision>(), new List<DownloadDecision>(), new List<DownloadDecision>()));
+                .Returns(Task.FromResult(new ProcessedDecisions(new List<DownloadDecision>(), new List<DownloadDecision>(), new List<DownloadDecision>())));
         }
 
         [Test]
diff --git a/src/NzbDrone.Core.Test/IndexerSearchTests/ReleaseSearchServiceFixture.cs b/src/NzbDrone.Core.Test/IndexerSearchTests/ReleaseSearchServiceFixture.cs
index 5fc1569f3..b798347b5 100644
--- a/src/NzbDrone.Core.Test/IndexerSearchTests/ReleaseSearchServiceFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerSearchTests/ReleaseSearchServiceFixture.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using Moq;
@@ -60,13 +61,13 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
 
             _mockIndexer.Setup(v => v.Fetch(It.IsAny<BookSearchCriteria>()))
                 .Callback<BookSearchCriteria>(s => result.Add(s))
-                .Returns(new List<Parser.Model.ReleaseInfo>());
+                .Returns(Task.FromResult<IList<Parser.Model.ReleaseInfo>>(new List<Parser.Model.ReleaseInfo>()));
 
             return result;
         }
 
         [Test]
-        public void Tags_IndexerTags_AuthorNoTags_IndexerNotIncluded()
+        public async Task Tags_IndexerTags_AuthorNoTags_IndexerNotIncluded()
         {
             _mockIndexer.SetupGet(s => s.Definition).Returns(new IndexerDefinition
             {
@@ -76,7 +77,7 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
 
             var allCriteria = WatchForSearchCriteria();
 
-            Subject.BookSearch(_firstBook, false, true, false);
+            await Subject.BookSearch(_firstBook, false, true, false);
 
             var criteria = allCriteria.OfType<BookSearchCriteria>().ToList();
 
@@ -84,7 +85,7 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
         }
 
         [Test]
-        public void Tags_IndexerNoTags_AuthorTags_IndexerIncluded()
+        public async Task Tags_IndexerNoTags_AuthorTags_IndexerIncluded()
         {
             _mockIndexer.SetupGet(s => s.Definition).Returns(new IndexerDefinition
             {
@@ -102,7 +103,7 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
 
             var allCriteria = WatchForSearchCriteria();
 
-            Subject.BookSearch(_firstBook, false, true, false);
+            await Subject.BookSearch(_firstBook, false, true, false);
 
             var criteria = allCriteria.OfType<BookSearchCriteria>().ToList();
 
@@ -110,7 +111,7 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
         }
 
         [Test]
-        public void Tags_IndexerAndAuthorTagsMatch_IndexerIncluded()
+        public async Task Tags_IndexerAndAuthorTagsMatch_IndexerIncluded()
         {
             _mockIndexer.SetupGet(s => s.Definition).Returns(new IndexerDefinition
             {
@@ -129,7 +130,7 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
 
             var allCriteria = WatchForSearchCriteria();
 
-            Subject.BookSearch(_firstBook, false, true, false);
+            await Subject.BookSearch(_firstBook, false, true, false);
 
             var criteria = allCriteria.OfType<BookSearchCriteria>().ToList();
 
@@ -137,7 +138,7 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
         }
 
         [Test]
-        public void Tags_IndexerAndAuthorTagsMismatch_IndexerNotIncluded()
+        public async Task Tags_IndexerAndAuthorTagsMismatch_IndexerNotIncluded()
         {
             _mockIndexer.SetupGet(s => s.Definition).Returns(new IndexerDefinition
             {
@@ -156,7 +157,7 @@ namespace NzbDrone.Core.Test.IndexerSearchTests
 
             var allCriteria = WatchForSearchCriteria();
 
-            Subject.BookSearch(_firstBook, false, true, false);
+            await Subject.BookSearch(_firstBook, false, true, false);
 
             var criteria = allCriteria.OfType<BookSearchCriteria>().ToList();
 
diff --git a/src/NzbDrone.Core.Test/IndexerTests/FileListTests/FileListFixture.cs b/src/NzbDrone.Core.Test/IndexerTests/FileListTests/FileListFixture.cs
index 732825188..995332eca 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/FileListTests/FileListFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/FileListTests/FileListFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using System.Net.Http;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -26,15 +27,15 @@ namespace NzbDrone.Core.Test.IndexerTests.FileListTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_FileList()
+        public async Task should_parse_recent_feed_from_FileList()
         {
             var recentFeed = ReadAllText(@"Files/Indexers/FileList/RecentFeed.json");
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(2);
             releases.First().Should().BeOfType<TorrentInfo>();
diff --git a/src/NzbDrone.Core.Test/IndexerTests/GazelleTests/GazelleFixture.cs b/src/NzbDrone.Core.Test/IndexerTests/GazelleTests/GazelleFixture.cs
index 76a1325ba..deaec8edc 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/GazelleTests/GazelleFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/GazelleTests/GazelleFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using System.Net.Http;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -30,24 +31,24 @@ namespace NzbDrone.Core.Test.IndexerTests.GazelleTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_gazelle()
+        public async Task should_parse_recent_feed_from_gazelle()
         {
             var recentFeed = ReadAllText(@"Files/Indexers/Gazelle/Gazelle.json");
             var indexFeed = ReadAllText(@"Files/Indexers/Gazelle/GazelleIndex.json");
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get && v.Url.FullUri.Contains("ajax.php?action=browse"))))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader { ContentType = "application/json" }, recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get && v.Url.FullUri.Contains("ajax.php?action=browse"))))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader { ContentType = "application/json" }, recentFeed)));
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Post && v.Url.FullUri.Contains("ajax.php?action=index"))))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), indexFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Post && v.Url.FullUri.Contains("ajax.php?action=index"))))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), indexFeed)));
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Post && v.Url.FullUri.Contains("login.php"))))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), indexFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Post && v.Url.FullUri.Contains("login.php"))))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), indexFeed)));
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(4);
 
diff --git a/src/NzbDrone.Core.Test/IndexerTests/IPTorrentsTests/IPTorrentsFixture.cs b/src/NzbDrone.Core.Test/IndexerTests/IPTorrentsTests/IPTorrentsFixture.cs
index 14238d93f..890acf429 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/IPTorrentsTests/IPTorrentsFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/IPTorrentsTests/IPTorrentsFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using System.Net.Http;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -84,15 +85,15 @@ namespace NzbDrone.Core.Test.IndexerTests.IPTorrentsTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_IPTorrents()
+        public async Task should_parse_recent_feed_from_IPTorrents()
         {
             var recentFeed = ReadAllText(@"Files/Indexers/IPTorrents/IPTorrents.xml");
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(5);
             releases.First().Should().BeOfType<TorrentInfo>();
diff --git a/src/NzbDrone.Core.Test/IndexerTests/NewznabTests/NewznabFixture.cs b/src/NzbDrone.Core.Test/IndexerTests/NewznabTests/NewznabFixture.cs
index 8dfa3fccb..005e2dabc 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/NewznabTests/NewznabFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/NewznabTests/NewznabFixture.cs
@@ -2,6 +2,7 @@ using System;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -39,15 +40,15 @@ namespace NzbDrone.Core.Test.IndexerTests.NewznabTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_newznab_nzb_su()
+        public async Task should_parse_recent_feed_from_newznab_nzb_su()
         {
             var recentFeed = ReadAllText(@"Files/Indexers/Newznab/newznab_nzb_su.xml");
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(100);
 
@@ -83,7 +84,7 @@ namespace NzbDrone.Core.Test.IndexerTests.NewznabTests
         }
 
         [Test]
-        public void should_record_indexer_failure_if_caps_throw()
+        public async Task should_record_indexer_failure_if_caps_throw()
         {
             var request = new HttpRequest("http://my.indexer.com");
             var response = new HttpResponse(request, new HttpHeader(), new byte[0], (HttpStatusCode)429);
@@ -96,7 +97,9 @@ namespace NzbDrone.Core.Test.IndexerTests.NewznabTests
             _caps.MaxPageSize = 30;
             _caps.DefaultPageSize = 25;
 
-            Subject.FetchRecent().Should().BeEmpty();
+            var releases = await Subject.FetchRecent();
+
+            releases.Should().BeEmpty();
 
             Mocker.GetMock<IIndexerStatusService>()
                   .Verify(v => v.RecordFailure(It.IsAny<int>(), TimeSpan.FromMinutes(5.0)), Times.Once());
diff --git a/src/NzbDrone.Core.Test/IndexerTests/NyaaTests/NyaaFixture.cs b/src/NzbDrone.Core.Test/IndexerTests/NyaaTests/NyaaFixture.cs
index 2d2d957d3..14755d2b2 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/NyaaTests/NyaaFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/NyaaTests/NyaaFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using System.Net.Http;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -26,15 +27,15 @@ namespace NzbDrone.Core.Test.IndexerTests.NyaaTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_Nyaa()
+        public async Task should_parse_recent_feed_from_Nyaa()
         {
             var recentFeed = ReadAllText(@"Files/Indexers/Nyaa/Nyaa.xml");
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(4);
             releases.First().Should().BeOfType<TorrentInfo>();
diff --git a/src/NzbDrone.Core.Test/IndexerTests/TorrentRssIndexerTests/TestTorrentRssIndexer.cs b/src/NzbDrone.Core.Test/IndexerTests/TorrentRssIndexerTests/TestTorrentRssIndexer.cs
index 110db4ec2..d969c5653 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/TorrentRssIndexerTests/TestTorrentRssIndexer.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/TorrentRssIndexerTests/TestTorrentRssIndexer.cs
@@ -22,7 +22,7 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         {
             var result = new List<ValidationFailure>();
             SetupNLog(); // Enable this to enable trace logging with nlog for debugging purposes
-            Test(result);
+            Test(result).GetAwaiter().GetResult();
             return result;
         }
 
diff --git a/src/NzbDrone.Core.Test/IndexerTests/TorrentRssIndexerTests/TorrentRssIndexerFixture.cs b/src/NzbDrone.Core.Test/IndexerTests/TorrentRssIndexerTests/TorrentRssIndexerFixture.cs
index 506e8ad18..e25421379 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/TorrentRssIndexerTests/TorrentRssIndexerFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/TorrentRssIndexerTests/TorrentRssIndexerFixture.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -34,17 +35,21 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         {
             var recentFeed = ReadAllText(@"Files/Indexers/" + rssXmlFile);
 
+            Mocker.GetMock<IHttpClient>()
+                .Setup(o => o.ExecuteAsync(It.IsAny<HttpRequest>()))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
+
             Mocker.GetMock<IHttpClient>()
                 .Setup(o => o.Execute(It.IsAny<HttpRequest>()))
                 .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
         }
 
         [Test]
-        public void should_parse_recent_feed_from_ImmortalSeed()
+        public async Task should_parse_recent_feed_from_ImmortalSeed()
         {
             GivenRecentFeedResponse("TorrentRss/ImmortalSeed.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(50);
             releases.First().Should().BeOfType<TorrentInfo>();
@@ -66,11 +71,11 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_Ezrss()
+        public async Task should_parse_recent_feed_from_Ezrss()
         {
             GivenRecentFeedResponse("TorrentRss/Ezrss.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(3);
             releases.First().Should().BeOfType<TorrentInfo>();
@@ -92,13 +97,13 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_ShowRSS_info()
+        public async Task should_parse_recent_feed_from_ShowRSS_info()
         {
             Subject.Definition.Settings.As<TorrentRssIndexerSettings>().AllowZeroSize = true;
 
             GivenRecentFeedResponse("TorrentRss/ShowRSS.info.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(5);
             releases.First().Should().BeOfType<TorrentInfo>();
@@ -120,13 +125,13 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_Doki()
+        public async Task should_parse_recent_feed_from_Doki()
         {
             Subject.Definition.Settings.As<TorrentRssIndexerSettings>().AllowZeroSize = true;
 
             GivenRecentFeedResponse("TorrentRss/Doki.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(5);
             releases.First().Should().BeOfType<TorrentInfo>();
@@ -148,11 +153,11 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_ExtraTorrents()
+        public async Task should_parse_recent_feed_from_ExtraTorrents()
         {
             GivenRecentFeedResponse("TorrentRss/ExtraTorrents.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(5);
             releases.First().Should().BeOfType<TorrentInfo>();
@@ -174,11 +179,11 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_LimeTorrents()
+        public async Task should_parse_recent_feed_from_LimeTorrents()
         {
             GivenRecentFeedResponse("TorrentRss/LimeTorrents.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(5);
             releases.First().Should().BeOfType<TorrentInfo>();
@@ -200,11 +205,11 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_AnimeTosho_without_size()
+        public async Task should_parse_recent_feed_from_AnimeTosho_without_size()
         {
             GivenRecentFeedResponse("TorrentRss/AnimeTosho_NoSize.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(2);
             releases.First().Should().BeOfType<TorrentInfo>();
@@ -226,11 +231,11 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_multi_enclosure_from_AnimeTosho()
+        public async Task should_parse_multi_enclosure_from_AnimeTosho()
         {
             GivenRecentFeedResponse("TorrentRss/AnimeTosho_NoSize.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(2);
             releases.Last().Should().BeOfType<TorrentInfo>();
@@ -243,11 +248,11 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_AlphaRatio()
+        public async Task should_parse_recent_feed_from_AlphaRatio()
         {
             GivenRecentFeedResponse("TorrentRss/AlphaRatio.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(2);
             releases.Last().Should().BeOfType<TorrentInfo>();
@@ -260,12 +265,12 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_EveolutionWorld_without_size()
+        public async Task should_parse_recent_feed_from_EveolutionWorld_without_size()
         {
             Subject.Definition.Settings.As<TorrentRssIndexerSettings>().AllowZeroSize = true;
             GivenRecentFeedResponse("TorrentRss/EvolutionWorld.xml");
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(2);
             releases.First().Should().BeOfType<TorrentInfo>();
@@ -287,11 +292,13 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentRssIndexerTests
         }
 
         [Test]
-        public void should_record_indexer_failure_if_unsupported_feed()
+        public async Task should_record_indexer_failure_if_unsupported_feed()
         {
             GivenRecentFeedResponse("TorrentRss/invalid/TorrentDay_NoPubDate.xml");
 
-            Subject.FetchRecent().Should().BeEmpty();
+            var releases = await Subject.FetchRecent();
+
+            releases.Should().BeEmpty();
 
             Mocker.GetMock<IIndexerStatusService>()
                   .Verify(v => v.RecordFailure(It.IsAny<int>(), TimeSpan.Zero), Times.Once());
diff --git a/src/NzbDrone.Core.Test/IndexerTests/TorrentleechTests/TorrentleechFixture.cs b/src/NzbDrone.Core.Test/IndexerTests/TorrentleechTests/TorrentleechFixture.cs
index 59a284276..a40b246d2 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/TorrentleechTests/TorrentleechFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/TorrentleechTests/TorrentleechFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using System.Net.Http;
+using System.Threading.Tasks;
 using FluentAssertions;
 using Moq;
 using NUnit.Framework;
@@ -26,15 +27,15 @@ namespace NzbDrone.Core.Test.IndexerTests.TorrentleechTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_Torrentleech()
+        public async Task should_parse_recent_feed_from_Torrentleech()
         {
             var recentFeed = ReadAllText(@"Files/Indexers/Torrentleech/Torrentleech.xml");
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(5);
             releases.First().Should().BeOfType<TorrentInfo>();
diff --git a/src/NzbDrone.Core.Test/IndexerTests/TorznabTests/TorznabFixture.cs b/src/NzbDrone.Core.Test/IndexerTests/TorznabTests/TorznabFixture.cs
index 91b5c38ad..7098d758f 100644
--- a/src/NzbDrone.Core.Test/IndexerTests/TorznabTests/TorznabFixture.cs
+++ b/src/NzbDrone.Core.Test/IndexerTests/TorznabTests/TorznabFixture.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Linq;
 using System.Net.Http;
+using System.Threading.Tasks;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using Moq;
@@ -44,15 +45,15 @@ namespace NzbDrone.Core.Test.IndexerTests.TorznabTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_torznab_hdaccess_net()
+        public async Task should_parse_recent_feed_from_torznab_hdaccess_net()
         {
             var recentFeed = ReadAllText(@"Files/Indexers/Torznab/torznab_hdaccess_net.xml");
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(5);
 
@@ -73,15 +74,15 @@ namespace NzbDrone.Core.Test.IndexerTests.TorznabTests
         }
 
         [Test]
-        public void should_parse_recent_feed_from_torznab_tpb()
+        public async Task should_parse_recent_feed_from_torznab_tpb()
         {
             var recentFeed = ReadAllText(@"Files/Indexers/Torznab/torznab_tpb.xml");
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
-            var releases = Subject.FetchRecent();
+            var releases = await Subject.FetchRecent();
 
             releases.Should().HaveCount(5);
 
@@ -140,8 +141,8 @@ namespace NzbDrone.Core.Test.IndexerTests.TorznabTests
             (Subject.Definition.Settings as TorznabSettings).BaseUrl = baseUrl;
 
             Mocker.GetMock<IHttpClient>()
-                .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
             var result = new NzbDroneValidationResult(Subject.Test());
             result.IsValid.Should().BeTrue();
@@ -155,8 +156,8 @@ namespace NzbDrone.Core.Test.IndexerTests.TorznabTests
             var recentFeed = ReadAllText(@"Files/Indexers/Torznab/torznab_tpb.xml");
 
             Mocker.GetMock<IHttpClient>()
-                  .Setup(o => o.Execute(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), recentFeed));
+                  .Setup(o => o.ExecuteAsync(It.Is<HttpRequest>(v => v.Method == HttpMethod.Get)))
+                  .Returns<HttpRequest>(r => Task.FromResult(new HttpResponse(r, new HttpHeader(), recentFeed)));
 
             (Subject.Definition.Settings as TorznabSettings).ApiPath = apiPath;
 
diff --git a/src/NzbDrone.Core/Download/Clients/Pneumatic/Pneumatic.cs b/src/NzbDrone.Core/Download/Clients/Pneumatic/Pneumatic.cs
index 61e4838b6..3e080732b 100644
--- a/src/NzbDrone.Core/Download/Clients/Pneumatic/Pneumatic.cs
+++ b/src/NzbDrone.Core/Download/Clients/Pneumatic/Pneumatic.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Threading.Tasks;
 using FluentValidation.Results;
 using NLog;
 using NzbDrone.Common.Disk;
@@ -32,7 +33,7 @@ namespace NzbDrone.Core.Download.Clients.Pneumatic
 
         public override DownloadProtocol Protocol => DownloadProtocol.Usenet;
 
-        public override string Download(RemoteBook remoteBook, IIndexer indexer)
+        public override async Task<string> Download(RemoteBook remoteBook, IIndexer indexer)
         {
             var url = remoteBook.Release.DownloadUrl;
             var title = remoteBook.Release.Title;
@@ -48,7 +49,7 @@ namespace NzbDrone.Core.Download.Clients.Pneumatic
             var nzbFile = Path.Combine(Settings.NzbFolder, title + ".nzb");
 
             _logger.Debug("Downloading NZB from: {0} to: {1}", url, nzbFile);
-            _httpClient.DownloadFile(url, nzbFile);
+            await _httpClient.DownloadFileAsync(url, nzbFile);
 
             _logger.Debug("NZB Download succeeded, saved to: {0}", nzbFile);
 
diff --git a/src/NzbDrone.Core/Download/DownloadClientBase.cs b/src/NzbDrone.Core/Download/DownloadClientBase.cs
index dfe997919..193759191 100644
--- a/src/NzbDrone.Core/Download/DownloadClientBase.cs
+++ b/src/NzbDrone.Core/Download/DownloadClientBase.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using FluentValidation.Results;
 using NLog;
 using NzbDrone.Common.Disk;
@@ -58,7 +59,7 @@ namespace NzbDrone.Core.Download
             get;
         }
 
-        public abstract string Download(RemoteBook remoteBook, IIndexer indexer);
+        public abstract Task<string> Download(RemoteBook remoteBook, IIndexer indexer);
         public abstract IEnumerable<DownloadClientItem> GetItems();
 
         public virtual DownloadClientItem GetImportItem(DownloadClientItem item, DownloadClientItem previousImportAttempt)
diff --git a/src/NzbDrone.Core/Download/DownloadService.cs b/src/NzbDrone.Core/Download/DownloadService.cs
index 349599b9b..924581da4 100644
--- a/src/NzbDrone.Core/Download/DownloadService.cs
+++ b/src/NzbDrone.Core/Download/DownloadService.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.EnsureThat;
 using NzbDrone.Common.Extensions;
@@ -16,7 +17,7 @@ namespace NzbDrone.Core.Download
 {
     public interface IDownloadService
     {
-        void DownloadReport(RemoteBook remoteBook);
+        Task DownloadReport(RemoteBook remoteBook);
     }
 
     public class DownloadService : IDownloadService
@@ -49,15 +50,23 @@ namespace NzbDrone.Core.Download
             _logger = logger;
         }
 
-        public void DownloadReport(RemoteBook remoteBook)
+        public async Task DownloadReport(RemoteBook remoteBook)
+        {
+            var filterBlockedClients = remoteBook.Release.PendingReleaseReason == PendingReleaseReason.DownloadClientUnavailable;
+
+            var tags = remoteBook.Author?.Tags;
+
+            var downloadClient = _downloadClientProvider.GetDownloadClient(remoteBook.Release.DownloadProtocol, remoteBook.Release.IndexerId, filterBlockedClients, tags);
+
+            await DownloadReport(remoteBook, downloadClient);
+        }
+
+        private async Task DownloadReport(RemoteBook remoteBook, IDownloadClient downloadClient)
         {
             Ensure.That(remoteBook.Author, () => remoteBook.Author).IsNotNull();
             Ensure.That(remoteBook.Books, () => remoteBook.Books).HasItems();
 
             var downloadTitle = remoteBook.Release.Title;
-            var filterBlockedClients = remoteBook.Release.PendingReleaseReason == PendingReleaseReason.DownloadClientUnavailable;
-            var tags = remoteBook.Author?.Tags;
-            var downloadClient = _downloadClientProvider.GetDownloadClient(remoteBook.Release.DownloadProtocol, remoteBook.Release.IndexerId, filterBlockedClients, tags);
 
             if (downloadClient == null)
             {
@@ -71,7 +80,7 @@ namespace NzbDrone.Core.Download
             if (remoteBook.Release.DownloadUrl.IsNotNullOrWhiteSpace() && !remoteBook.Release.DownloadUrl.StartsWith("magnet:"))
             {
                 var url = new HttpUri(remoteBook.Release.DownloadUrl);
-                _rateLimitService.WaitAndPulse(url.Host, TimeSpan.FromSeconds(2));
+                await _rateLimitService.WaitAndPulseAsync(url.Host, TimeSpan.FromSeconds(2));
             }
 
             IIndexer indexer = null;
@@ -84,7 +93,7 @@ namespace NzbDrone.Core.Download
             string downloadClientId;
             try
             {
-                downloadClientId = downloadClient.Download(remoteBook, indexer);
+                downloadClientId = await downloadClient.Download(remoteBook, indexer);
                 _downloadClientStatusService.RecordSuccess(downloadClient.Definition.Id);
                 _indexerStatusService.RecordSuccess(remoteBook.Release.IndexerId);
             }
@@ -100,8 +109,7 @@ namespace NzbDrone.Core.Download
             }
             catch (ReleaseDownloadException ex)
             {
-                var http429 = ex.InnerException as TooManyRequestsException;
-                if (http429 != null)
+                if (ex.InnerException is TooManyRequestsException http429)
                 {
                     _indexerStatusService.RecordFailure(remoteBook.Release.IndexerId, http429.RetryAfter);
                 }
diff --git a/src/NzbDrone.Core/Download/IDownloadClient.cs b/src/NzbDrone.Core/Download/IDownloadClient.cs
index 711c10209..2cecd5589 100644
--- a/src/NzbDrone.Core/Download/IDownloadClient.cs
+++ b/src/NzbDrone.Core/Download/IDownloadClient.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using NzbDrone.Core.Indexers;
 using NzbDrone.Core.Parser.Model;
 using NzbDrone.Core.ThingiProvider;
@@ -8,7 +9,7 @@ namespace NzbDrone.Core.Download
     public interface IDownloadClient : IProvider
     {
         DownloadProtocol Protocol { get; }
-        string Download(RemoteBook remoteBook, IIndexer indexer);
+        Task<string> Download(RemoteBook remoteBook, IIndexer indexer);
         IEnumerable<DownloadClientItem> GetItems();
         DownloadClientItem GetImportItem(DownloadClientItem item, DownloadClientItem previousImportAttempt);
         void RemoveItem(DownloadClientItem item, bool deleteData);
diff --git a/src/NzbDrone.Core/Download/ProcessDownloadDecisions.cs b/src/NzbDrone.Core/Download/ProcessDownloadDecisions.cs
index aa7ab3f70..24228a357 100644
--- a/src/NzbDrone.Core/Download/ProcessDownloadDecisions.cs
+++ b/src/NzbDrone.Core/Download/ProcessDownloadDecisions.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Core.DecisionEngine;
 using NzbDrone.Core.Download.Clients;
@@ -12,7 +13,7 @@ namespace NzbDrone.Core.Download
 {
     public interface IProcessDownloadDecisions
     {
-        ProcessedDecisions ProcessDecisions(List<DownloadDecision> decisions);
+        Task<ProcessedDecisions> ProcessDecisions(List<DownloadDecision> decisions);
     }
 
     public class ProcessDownloadDecisions : IProcessDownloadDecisions
@@ -33,7 +34,7 @@ namespace NzbDrone.Core.Download
             _logger = logger;
         }
 
-        public ProcessedDecisions ProcessDecisions(List<DownloadDecision> decisions)
+        public async Task<ProcessedDecisions> ProcessDecisions(List<DownloadDecision> decisions)
         {
             var qualifiedReports = GetQualifiedReports(decisions);
             var prioritizedDecisions = _prioritizeDownloadDecision.PrioritizeDecisions(qualifiedReports);
@@ -75,7 +76,7 @@ namespace NzbDrone.Core.Download
                 try
                 {
                     _logger.Trace("Grabbing from Indexer {0} at priority {1}.", remoteBook.Release.Indexer, remoteBook.Release.IndexerPriority);
-                    _downloadService.DownloadReport(remoteBook);
+                    await _downloadService.DownloadReport(remoteBook);
                     grabbed.Add(report);
                 }
                 catch (ReleaseUnavailableException)
diff --git a/src/NzbDrone.Core/Download/TorrentClientBase.cs b/src/NzbDrone.Core/Download/TorrentClientBase.cs
index bf398a898..a5ffd4b5e 100644
--- a/src/NzbDrone.Core/Download/TorrentClientBase.cs
+++ b/src/NzbDrone.Core/Download/TorrentClientBase.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Net;
+using System.Threading.Tasks;
 using MonoTorrent;
 using NLog;
 using NzbDrone.Common.Disk;
@@ -41,7 +42,7 @@ namespace NzbDrone.Core.Download
         protected abstract string AddFromMagnetLink(RemoteBook remoteBook, string hash, string magnetLink);
         protected abstract string AddFromTorrentFile(RemoteBook remoteBook, string hash, string filename, byte[] fileContent);
 
-        public override string Download(RemoteBook remoteBook, IIndexer indexer)
+        public override async Task<string> Download(RemoteBook remoteBook, IIndexer indexer)
         {
             var torrentInfo = remoteBook.Release as TorrentInfo;
 
@@ -68,7 +69,7 @@ namespace NzbDrone.Core.Download
                 {
                     try
                     {
-                        return DownloadFromWebUrl(remoteBook, indexer, torrentUrl);
+                        return await DownloadFromWebUrl(remoteBook, indexer, torrentUrl);
                     }
                     catch (Exception ex)
                     {
@@ -114,14 +115,14 @@ namespace NzbDrone.Core.Download
 
                 if (torrentUrl.IsNotNullOrWhiteSpace())
                 {
-                    return DownloadFromWebUrl(remoteBook, indexer, torrentUrl);
+                    return await DownloadFromWebUrl(remoteBook, indexer, torrentUrl);
                 }
             }
 
             return null;
         }
 
-        private string DownloadFromWebUrl(RemoteBook remoteBook, IIndexer indexer, string torrentUrl)
+        private async Task<string> DownloadFromWebUrl(RemoteBook remoteBook, IIndexer indexer, string torrentUrl)
         {
             byte[] torrentFile = null;
 
@@ -132,7 +133,7 @@ namespace NzbDrone.Core.Download
                 request.Headers.Accept = "application/x-bittorrent";
                 request.AllowAutoRedirect = false;
 
-                var response = _httpClient.Get(request);
+                var response = await _httpClient.GetAsync(request);
 
                 if (response.StatusCode == HttpStatusCode.MovedPermanently ||
                     response.StatusCode == HttpStatusCode.Found ||
@@ -151,7 +152,7 @@ namespace NzbDrone.Core.Download
 
                         request.Url += new HttpUri(locationHeader);
 
-                        return DownloadFromWebUrl(remoteBook, indexer, request.Url.ToString());
+                        return await DownloadFromWebUrl(remoteBook, indexer, request.Url.ToString());
                     }
 
                     throw new WebException("Remote website tried to redirect without providing a location.");
diff --git a/src/NzbDrone.Core/Download/UsenetClientBase.cs b/src/NzbDrone.Core/Download/UsenetClientBase.cs
index 2bd9b2d23..b4bca217a 100644
--- a/src/NzbDrone.Core/Download/UsenetClientBase.cs
+++ b/src/NzbDrone.Core/Download/UsenetClientBase.cs
@@ -1,4 +1,5 @@
 using System.Net;
+using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.Disk;
 using NzbDrone.Common.Http;
@@ -34,7 +35,7 @@ namespace NzbDrone.Core.Download
 
         protected abstract string AddFromNzbFile(RemoteBook remoteBook, string filename, byte[] fileContent);
 
-        public override string Download(RemoteBook remoteBook, IIndexer indexer)
+        public override async Task<string> Download(RemoteBook remoteBook, IIndexer indexer)
         {
             var url = remoteBook.Release.DownloadUrl;
             var filename = FileNameBuilder.CleanFileName(remoteBook.Release.Title) + ".nzb";
@@ -46,7 +47,9 @@ namespace NzbDrone.Core.Download
                 var request = indexer?.GetDownloadRequest(url) ?? new HttpRequest(url);
                 request.RateLimitKey = remoteBook?.Release?.IndexerId.ToString();
 
-                nzbData = _httpClient.Get(request).ResponseData;
+                var response = await _httpClient.GetAsync(request);
+
+                nzbData = response.ResponseData;
 
                 _logger.Debug("Downloaded nzb for release '{0}' finished ({1} bytes from {2})", remoteBook.Release.Title, nzbData.Length, url);
             }
diff --git a/src/NzbDrone.Core/IndexerSearch/AuthorSearchService.cs b/src/NzbDrone.Core/IndexerSearch/AuthorSearchService.cs
index 376239d2b..1e01ba913 100644
--- a/src/NzbDrone.Core/IndexerSearch/AuthorSearchService.cs
+++ b/src/NzbDrone.Core/IndexerSearch/AuthorSearchService.cs
@@ -22,8 +22,8 @@ namespace NzbDrone.Core.IndexerSearch
 
         public void Execute(AuthorSearchCommand message)
         {
-            var decisions = _releaseSearchService.AuthorSearch(message.AuthorId, false, message.Trigger == CommandTrigger.Manual, false);
-            var processed = _processDownloadDecisions.ProcessDecisions(decisions);
+            var decisions = _releaseSearchService.AuthorSearch(message.AuthorId, false, message.Trigger == CommandTrigger.Manual, false).GetAwaiter().GetResult();
+            var processed = _processDownloadDecisions.ProcessDecisions(decisions).GetAwaiter().GetResult();
 
             _logger.ProgressInfo("Author search completed. {0} reports downloaded.", processed.Grabbed.Count);
         }
diff --git a/src/NzbDrone.Core/IndexerSearch/BookSearchService.cs b/src/NzbDrone.Core/IndexerSearch/BookSearchService.cs
index 04bdf55be..f983602ad 100644
--- a/src/NzbDrone.Core/IndexerSearch/BookSearchService.cs
+++ b/src/NzbDrone.Core/IndexerSearch/BookSearchService.cs
@@ -2,11 +2,11 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
+using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.Instrumentation.Extensions;
 using NzbDrone.Core.Books;
 using NzbDrone.Core.Datastore;
-using NzbDrone.Core.DecisionEngine;
 using NzbDrone.Core.Download;
 using NzbDrone.Core.Messaging.Commands;
 using NzbDrone.Core.Queue;
@@ -39,16 +39,15 @@ namespace NzbDrone.Core.IndexerSearch
             _logger = logger;
         }
 
-        private void SearchForMissingBooks(List<Book> books, bool userInvokedSearch)
+        private async Task SearchForMissingBooks(List<Book> books, bool userInvokedSearch)
         {
             _logger.ProgressInfo("Performing missing search for {0} books", books.Count);
             var downloadedCount = 0;
 
             foreach (var book in books)
             {
-                List<DownloadDecision> decisions;
-                decisions = _releaseSearchService.BookSearch(book.Id, false, userInvokedSearch, false);
-                var processed = _processDownloadDecisions.ProcessDecisions(decisions);
+                var decisions = await _releaseSearchService.BookSearch(book.Id, false, userInvokedSearch, false);
+                var processed = await _processDownloadDecisions.ProcessDecisions(decisions);
 
                 downloadedCount += processed.Grabbed.Count;
             }
@@ -60,9 +59,8 @@ namespace NzbDrone.Core.IndexerSearch
         {
             foreach (var bookId in message.BookIds)
             {
-                var decisions =
-                    _releaseSearchService.BookSearch(bookId, false, message.Trigger == CommandTrigger.Manual, false);
-                var processed = _processDownloadDecisions.ProcessDecisions(decisions);
+                var decisions = _releaseSearchService.BookSearch(bookId, false, message.Trigger == CommandTrigger.Manual, false).GetAwaiter().GetResult();
+                var processed = _processDownloadDecisions.ProcessDecisions(decisions).GetAwaiter().GetResult();
 
                 _logger.ProgressInfo("Book search completed. {0} reports downloaded.", processed.Grabbed.Count);
             }
@@ -106,7 +104,7 @@ namespace NzbDrone.Core.IndexerSearch
             var queue = _queueService.GetQueue().Where(q => q.Book != null).Select(q => q.Book.Id);
             var missing = books.Where(e => !queue.Contains(e.Id)).ToList();
 
-            SearchForMissingBooks(missing, message.Trigger == CommandTrigger.Manual);
+            SearchForMissingBooks(missing, message.Trigger == CommandTrigger.Manual).GetAwaiter().GetResult();
         }
 
         public void Execute(CutoffUnmetBookSearchCommand message)
@@ -132,7 +130,7 @@ namespace NzbDrone.Core.IndexerSearch
             var queue = _queueService.GetQueue().Where(q => q.Book != null).Select(q => q.Book.Id);
             var missing = books.Where(e => !queue.Contains(e.Id)).ToList();
 
-            SearchForMissingBooks(missing, message.Trigger == CommandTrigger.Manual);
+            SearchForMissingBooks(missing, message.Trigger == CommandTrigger.Manual).GetAwaiter().GetResult();
         }
     }
 }
diff --git a/src/NzbDrone.Core/IndexerSearch/ReleaseSearchService.cs b/src/NzbDrone.Core/IndexerSearch/ReleaseSearchService.cs
index 62d89ee47..dc4844bb9 100644
--- a/src/NzbDrone.Core/IndexerSearch/ReleaseSearchService.cs
+++ b/src/NzbDrone.Core/IndexerSearch/ReleaseSearchService.cs
@@ -5,7 +5,6 @@ using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.Extensions;
 using NzbDrone.Common.Instrumentation.Extensions;
-using NzbDrone.Common.TPL;
 using NzbDrone.Core.Books;
 using NzbDrone.Core.DecisionEngine;
 using NzbDrone.Core.Indexers;
@@ -16,8 +15,8 @@ namespace NzbDrone.Core.IndexerSearch
 {
     public interface ISearchForReleases
     {
-        List<DownloadDecision> BookSearch(int bookId, bool missingOnly, bool userInvokedSearch, bool interactiveSearch);
-        List<DownloadDecision> AuthorSearch(int authorId, bool missingOnly, bool userInvokedSearch, bool interactiveSearch);
+        Task<List<DownloadDecision>> BookSearch(int bookId, bool missingOnly, bool userInvokedSearch, bool interactiveSearch);
+        Task<List<DownloadDecision>> AuthorSearch(int authorId, bool missingOnly, bool userInvokedSearch, bool interactiveSearch);
     }
 
     public class ReleaseSearchService : ISearchForReleases
@@ -41,31 +40,31 @@ namespace NzbDrone.Core.IndexerSearch
             _logger = logger;
         }
 
-        public List<DownloadDecision> BookSearch(int bookId, bool missingOnly, bool userInvokedSearch, bool interactiveSearch)
+        public async Task<List<DownloadDecision>> BookSearch(int bookId, bool missingOnly, bool userInvokedSearch, bool interactiveSearch)
         {
             var downloadDecisions = new List<DownloadDecision>();
 
             var book = _bookService.GetBook(bookId);
 
-            var decisions = BookSearch(book, missingOnly, userInvokedSearch, interactiveSearch);
+            var decisions = await BookSearch(book, missingOnly, userInvokedSearch, interactiveSearch);
             downloadDecisions.AddRange(decisions);
 
             return DeDupeDecisions(downloadDecisions);
         }
 
-        public List<DownloadDecision> AuthorSearch(int authorId, bool missingOnly, bool userInvokedSearch, bool interactiveSearch)
+        public async Task<List<DownloadDecision>> AuthorSearch(int authorId, bool missingOnly, bool userInvokedSearch, bool interactiveSearch)
         {
             var downloadDecisions = new List<DownloadDecision>();
 
             var author = _authorService.GetAuthor(authorId);
 
-            var decisions = AuthorSearch(author, missingOnly, userInvokedSearch, interactiveSearch);
+            var decisions = await AuthorSearch(author, missingOnly, userInvokedSearch, interactiveSearch);
             downloadDecisions.AddRange(decisions);
 
             return DeDupeDecisions(downloadDecisions);
         }
 
-        public List<DownloadDecision> AuthorSearch(Author author, bool missingOnly, bool userInvokedSearch, bool interactiveSearch)
+        public async Task<List<DownloadDecision>> AuthorSearch(Author author, bool missingOnly, bool userInvokedSearch, bool interactiveSearch)
         {
             var searchSpec = Get<AuthorSearchCriteria>(author, userInvokedSearch, interactiveSearch);
             var books = _bookService.GetBooksByAuthor(author.Id);
@@ -74,10 +73,10 @@ namespace NzbDrone.Core.IndexerSearch
 
             searchSpec.Books = books;
 
-            return Dispatch(indexer => indexer.Fetch(searchSpec), searchSpec);
+            return await Dispatch(indexer => indexer.Fetch(searchSpec), searchSpec);
         }
 
-        public List<DownloadDecision> BookSearch(Book book, bool missingOnly, bool userInvokedSearch, bool interactiveSearch)
+        public async Task<List<DownloadDecision>> BookSearch(Book book, bool missingOnly, bool userInvokedSearch, bool interactiveSearch)
         {
             var author = _authorService.GetAuthor(book.AuthorId);
 
@@ -91,7 +90,7 @@ namespace NzbDrone.Core.IndexerSearch
                 searchSpec.BookYear = book.ReleaseDate.Value.Year;
             }
 
-            return Dispatch(indexer => indexer.Fetch(searchSpec), searchSpec);
+            return await Dispatch(indexer => indexer.Fetch(searchSpec), searchSpec);
         }
 
         private TSpec Get<TSpec>(Author author, List<Book> books, bool userInvokedSearch, bool interactiveSearch)
@@ -118,7 +117,7 @@ namespace NzbDrone.Core.IndexerSearch
             return spec;
         }
 
-        private List<DownloadDecision> Dispatch(Func<IIndexer, IEnumerable<ReleaseInfo>> searchAction, SearchCriteriaBase criteriaBase)
+        private async Task<List<DownloadDecision>> Dispatch(Func<IIndexer, Task<IList<ReleaseInfo>>> searchAction, SearchCriteriaBase criteriaBase)
         {
             var indexers = criteriaBase.InteractiveSearch ?
                 _indexerFactory.InteractiveSearchEnabled() :
@@ -127,42 +126,33 @@ namespace NzbDrone.Core.IndexerSearch
             // Filter indexers to untagged indexers and indexers with intersecting tags
             indexers = indexers.Where(i => i.Definition.Tags.Empty() || i.Definition.Tags.Intersect(criteriaBase.Author.Tags).Any()).ToList();
 
-            var reports = new List<ReleaseInfo>();
-
             _logger.ProgressInfo("Searching indexers for {0}. {1} active indexers", criteriaBase, indexers.Count);
 
-            var taskList = new List<Task>();
-            var taskFactory = new TaskFactory(TaskCreationOptions.LongRunning, TaskContinuationOptions.None);
+            var tasks = indexers.Select(indexer => DispatchIndexer(searchAction, indexer, criteriaBase));
 
-            foreach (var indexer in indexers)
-            {
-                var indexerLocal = indexer;
-
-                taskList.Add(taskFactory.StartNew(() =>
-                {
-                    try
-                    {
-                        var indexerReports = searchAction(indexerLocal);
-
-                        lock (reports)
-                        {
-                            reports.AddRange(indexerReports);
-                        }
-                    }
-                    catch (Exception e)
-                    {
-                        _logger.Error(e, "Error while searching for {0}", criteriaBase);
-                    }
-                }).LogExceptions());
-            }
+            var batch = await Task.WhenAll(tasks);
 
-            Task.WaitAll(taskList.ToArray());
+            var reports = batch.SelectMany(x => x).ToList();
 
             _logger.Debug("Total of {0} reports were found for {1} from {2} indexers", reports.Count, criteriaBase, indexers.Count);
 
             return _makeDownloadDecision.GetSearchDecision(reports, criteriaBase).ToList();
         }
 
+        private async Task<IList<ReleaseInfo>> DispatchIndexer(Func<IIndexer, Task<IList<ReleaseInfo>>> searchAction, IIndexer indexer, SearchCriteriaBase criteriaBase)
+        {
+            try
+            {
+                return await searchAction(indexer);
+            }
+            catch (Exception ex)
+            {
+                _logger.Error(ex, "Error while searching for {0}", criteriaBase);
+            }
+
+            return Array.Empty<ReleaseInfo>();
+        }
+
         private List<DownloadDecision> DeDupeDecisions(List<DownloadDecision> decisions)
         {
             // De-dupe reports by guid so duplicate results aren't returned. Pick the one with the least rejections and higher indexer priority.
diff --git a/src/NzbDrone.Core/Indexers/FetchAndParseRssService.cs b/src/NzbDrone.Core/Indexers/FetchAndParseRssService.cs
index 460f63e13..373e6998a 100644
--- a/src/NzbDrone.Core/Indexers/FetchAndParseRssService.cs
+++ b/src/NzbDrone.Core/Indexers/FetchAndParseRssService.cs
@@ -3,13 +3,12 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using NLog;
-using NzbDrone.Common.TPL;
 using NzbDrone.Core.Parser.Model;
 namespace NzbDrone.Core.Indexers
 {
     public interface IFetchAndParseRss
     {
-        List<ReleaseInfo> Fetch();
+        Task<List<ReleaseInfo>> Fetch();
     }
 
     public class FetchAndParseRssService : IFetchAndParseRss
@@ -23,54 +22,42 @@ namespace NzbDrone.Core.Indexers
             _logger = logger;
         }
 
-        public List<ReleaseInfo> Fetch()
+        public async Task<List<ReleaseInfo>> Fetch()
         {
-            var result = new List<ReleaseInfo>();
-
             var indexers = _indexerFactory.RssEnabled();
 
             if (!indexers.Any())
             {
                 _logger.Warn("No available indexers. check your configuration.");
-                return result;
+
+                return new List<ReleaseInfo>();
             }
 
             _logger.Debug("Available indexers {0}", indexers.Count);
 
-            var taskList = new List<Task>();
-            var taskFactory = new TaskFactory(TaskCreationOptions.LongRunning, TaskContinuationOptions.None);
+            var tasks = indexers.Select(FetchIndexer);
 
-            foreach (var indexer in indexers)
-            {
-                var indexerLocal = indexer;
+            var batch = await Task.WhenAll(tasks);
 
-                var task = taskFactory.StartNew(() =>
-                     {
-                         try
-                         {
-                             var indexerReports = indexerLocal.FetchRecent();
+            var result = batch.SelectMany(x => x).ToList();
 
-                             lock (result)
-                             {
-                                 _logger.Debug("Found {0} from {1}", indexerReports.Count, indexer.Name);
+            _logger.Debug("Found {0} reports", result.Count);
 
-                                 result.AddRange(indexerReports);
-                             }
-                         }
-                         catch (Exception e)
-                         {
-                             _logger.Error(e, "Error during RSS Sync");
-                         }
-                     }).LogExceptions();
+            return result;
+        }
 
-                taskList.Add(task);
+        private async Task<IList<ReleaseInfo>> FetchIndexer(IIndexer indexer)
+        {
+            try
+            {
+                return await indexer.FetchRecent();
+            }
+            catch (Exception ex)
+            {
+                _logger.Error(ex, "Error during RSS Sync");
             }
 
-            Task.WaitAll(taskList.ToArray());
-
-            _logger.Debug("Found {0} reports", result.Count);
-
-            return result;
+            return Array.Empty<ReleaseInfo>();
         }
     }
 }
diff --git a/src/NzbDrone.Core/Indexers/Gazelle/Gazelle.cs b/src/NzbDrone.Core/Indexers/Gazelle/Gazelle.cs
index 0f2f2df30..3e05a3818 100644
--- a/src/NzbDrone.Core/Indexers/Gazelle/Gazelle.cs
+++ b/src/NzbDrone.Core/Indexers/Gazelle/Gazelle.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using FluentValidation.Results;
 using NLog;
 using NzbDrone.Common.Cache;
@@ -68,11 +69,12 @@ namespace NzbDrone.Core.Indexers.Gazelle
             return settings;
         }
 
-        protected override void Test(List<ValidationFailure> failures)
+        protected override async Task Test(List<ValidationFailure> failures)
         {
             // Remove previous cookies when testing incase user or pwd change
             _authCookieCache.Remove(Settings.BaseUrl.Trim().TrimEnd('/'));
-            base.Test(failures);
+
+            await base.Test(failures);
         }
     }
 }
diff --git a/src/NzbDrone.Core/Indexers/Gazelle/GazelleRequestGenerator.cs b/src/NzbDrone.Core/Indexers/Gazelle/GazelleRequestGenerator.cs
index a64fa6643..0285a414c 100644
--- a/src/NzbDrone.Core/Indexers/Gazelle/GazelleRequestGenerator.cs
+++ b/src/NzbDrone.Core/Indexers/Gazelle/GazelleRequestGenerator.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Net.Http;
+using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.Cache;
 using NzbDrone.Common.Extensions;
@@ -43,17 +44,14 @@ namespace NzbDrone.Core.Indexers.Gazelle
 
         private IEnumerable<IndexerRequest> GetRequest(string searchParameters)
         {
-            Authenticate();
+            Authenticate().GetAwaiter().GetResult();
 
             var filter = "";
             if (searchParameters == null)
             {
             }
 
-            var request =
-                new IndexerRequest(
-                    $"{Settings.BaseUrl.Trim().TrimEnd('/')}/ajax.php?action=browse&searchstr={searchParameters}{filter}",
-                    HttpAccept.Json);
+            var request = new IndexerRequest($"{Settings.BaseUrl.Trim().TrimEnd('/')}/ajax.php?action=browse&searchstr={searchParameters}{filter}", HttpAccept.Json);
 
             var cookies = AuthCookieCache.Find(Settings.BaseUrl.Trim().TrimEnd('/'));
             foreach (var cookie in cookies)
@@ -64,36 +62,36 @@ namespace NzbDrone.Core.Indexers.Gazelle
             yield return request;
         }
 
-        private GazelleAuthResponse GetIndex(Dictionary<string, string> cookies)
+        private async Task<GazelleAuthResponse> GetIndex(Dictionary<string, string> cookies)
         {
             var indexRequestBuilder = new HttpRequestBuilder($"{Settings.BaseUrl.Trim().TrimEnd('/')}")
             {
-                LogResponseContent = true
+                LogResponseContent = true,
+                Method = HttpMethod.Post
             };
 
             indexRequestBuilder.SetCookies(cookies);
-            indexRequestBuilder.Method = HttpMethod.Post;
             indexRequestBuilder.Resource("ajax.php?action=index");
 
             var authIndexRequest = indexRequestBuilder
                 .Accept(HttpAccept.Json)
                 .Build();
 
-            var indexResponse = HttpClient.Execute(authIndexRequest);
+            var indexResponse = await HttpClient.ExecuteAsync(authIndexRequest);
 
             var result = Json.Deserialize<GazelleAuthResponse>(indexResponse.Content);
 
             return result;
         }
 
-        private void Authenticate()
+        private async Task Authenticate()
         {
             var requestBuilder = new HttpRequestBuilder($"{Settings.BaseUrl.Trim().TrimEnd('/')}")
             {
-                LogResponseContent = true
+                LogResponseContent = true,
+                Method = HttpMethod.Post
             };
 
-            requestBuilder.Method = HttpMethod.Post;
             requestBuilder.Resource("login.php");
             requestBuilder.PostProcess += r => r.RequestTimeout = TimeSpan.FromSeconds(15);
 
@@ -111,19 +109,20 @@ namespace NzbDrone.Core.Indexers.Gazelle
                     .Accept(HttpAccept.Json)
                     .Build();
 
-                var response = HttpClient.Execute(authLoginRequest);
+                var response = await HttpClient.ExecuteAsync(authLoginRequest);
 
                 cookies = response.GetCookies();
 
                 AuthCookieCache.Set(authKey, cookies);
             }
 
-            var index = GetIndex(cookies);
+            var index = await GetIndex(cookies);
 
             if (index == null || index.Status.IsNullOrWhiteSpace() || index.Status != "success")
             {
                 Logger.Debug("Gazelle authentication failed.");
                 AuthCookieCache.Remove(authKey);
+
                 throw new Exception("Failed to authenticate with Gazelle.");
             }
 
diff --git a/src/NzbDrone.Core/Indexers/HttpIndexerBase.cs b/src/NzbDrone.Core/Indexers/HttpIndexerBase.cs
index 7a05071f5..b0cffd4fb 100644
--- a/src/NzbDrone.Core/Indexers/HttpIndexerBase.cs
+++ b/src/NzbDrone.Core/Indexers/HttpIndexerBase.cs
@@ -40,31 +40,31 @@ namespace NzbDrone.Core.Indexers
             _httpClient = httpClient;
         }
 
-        public override IList<ReleaseInfo> FetchRecent()
+        public override Task<IList<ReleaseInfo>> FetchRecent()
         {
             if (!SupportsRss)
             {
-                return new List<ReleaseInfo>();
+                return Task.FromResult<IList<ReleaseInfo>>(Array.Empty<ReleaseInfo>());
             }
 
             return FetchReleases(g => g.GetRecentRequests(), true);
         }
 
-        public override IList<ReleaseInfo> Fetch(BookSearchCriteria searchCriteria)
+        public override Task<IList<ReleaseInfo>> Fetch(BookSearchCriteria searchCriteria)
         {
             if (!SupportsSearch)
             {
-                return new List<ReleaseInfo>();
+                return Task.FromResult<IList<ReleaseInfo>>(Array.Empty<ReleaseInfo>());
             }
 
             return FetchReleases(g => g.GetSearchRequests(searchCriteria));
         }
 
-        public override IList<ReleaseInfo> Fetch(AuthorSearchCriteria searchCriteria)
+        public override Task<IList<ReleaseInfo>> Fetch(AuthorSearchCriteria searchCriteria)
         {
             if (!SupportsSearch)
             {
-                return new List<ReleaseInfo>();
+                return Task.FromResult<IList<ReleaseInfo>>(Array.Empty<ReleaseInfo>());
             }
 
             return FetchReleases(g => g.GetSearchRequests(searchCriteria));
@@ -75,7 +75,7 @@ namespace NzbDrone.Core.Indexers
             return new HttpRequest(link);
         }
 
-        protected virtual IList<ReleaseInfo> FetchReleases(Func<IIndexerRequestGenerator, IndexerPageableRequestChain> pageableRequestChainSelector, bool isRecent = false)
+        protected virtual async Task<IList<ReleaseInfo>> FetchReleases(Func<IIndexerRequestGenerator, IndexerPageableRequestChain> pageableRequestChainSelector, bool isRecent = false)
         {
             var releases = new List<ReleaseInfo>();
             var url = string.Empty;
@@ -107,7 +107,7 @@ namespace NzbDrone.Core.Indexers
                         {
                             url = request.Url.FullUri;
 
-                            var page = FetchPage(request, parser);
+                            var page = await FetchPage(request, parser);
 
                             pagedReleases.AddRange(page);
 
@@ -271,9 +271,9 @@ namespace NzbDrone.Core.Indexers
             return PageSize != 0 && page.Count >= PageSize;
         }
 
-        protected virtual IList<ReleaseInfo> FetchPage(IndexerRequest request, IParseIndexerResponse parser)
+        protected virtual async Task<IList<ReleaseInfo>> FetchPage(IndexerRequest request, IParseIndexerResponse parser)
         {
-            var response = FetchIndexerResponse(request);
+            var response = await FetchIndexerResponse(request);
 
             try
             {
@@ -287,7 +287,7 @@ namespace NzbDrone.Core.Indexers
             }
         }
 
-        protected virtual IndexerResponse FetchIndexerResponse(IndexerRequest request)
+        protected virtual async Task<IndexerResponse> FetchIndexerResponse(IndexerRequest request)
         {
             _logger.Debug("Downloading Feed " + request.HttpRequest.ToString(false));
 
@@ -298,15 +298,17 @@ namespace NzbDrone.Core.Indexers
 
             request.HttpRequest.RateLimitKey = Definition.Id.ToString();
 
-            return new IndexerResponse(request, _httpClient.Execute(request.HttpRequest));
+            var response = await _httpClient.ExecuteAsync(request.HttpRequest);
+
+            return new IndexerResponse(request, response);
         }
 
-        protected override void Test(List<ValidationFailure> failures)
+        protected override async Task Test(List<ValidationFailure> failures)
         {
-            failures.AddIfNotNull(TestConnection());
+            failures.AddIfNotNull(await TestConnection());
         }
 
-        protected virtual ValidationFailure TestConnection()
+        protected virtual async Task<ValidationFailure> TestConnection()
         {
             try
             {
@@ -319,7 +321,7 @@ namespace NzbDrone.Core.Indexers
                     return new ValidationFailure(string.Empty, "No rss feed query available. This may be an issue with the indexer or your indexer category settings.");
                 }
 
-                var releases = FetchPage(firstRequest, parser);
+                var releases = await FetchPage(firstRequest, parser);
 
                 if (releases.Empty())
                 {
diff --git a/src/NzbDrone.Core/Indexers/IIndexer.cs b/src/NzbDrone.Core/Indexers/IIndexer.cs
index 57fcc72b3..f2be5626f 100644
--- a/src/NzbDrone.Core/Indexers/IIndexer.cs
+++ b/src/NzbDrone.Core/Indexers/IIndexer.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using NzbDrone.Common.Http;
 using NzbDrone.Core.IndexerSearch.Definitions;
 using NzbDrone.Core.Parser.Model;
@@ -12,9 +13,9 @@ namespace NzbDrone.Core.Indexers
         bool SupportsSearch { get; }
         DownloadProtocol Protocol { get; }
 
-        IList<ReleaseInfo> FetchRecent();
-        IList<ReleaseInfo> Fetch(BookSearchCriteria searchCriteria);
-        IList<ReleaseInfo> Fetch(AuthorSearchCriteria searchCriteria);
+        Task<IList<ReleaseInfo>> FetchRecent();
+        Task<IList<ReleaseInfo>> Fetch(BookSearchCriteria searchCriteria);
+        Task<IList<ReleaseInfo>> Fetch(AuthorSearchCriteria searchCriteria);
         HttpRequest GetDownloadRequest(string link);
     }
 }
diff --git a/src/NzbDrone.Core/Indexers/IndexerBase.cs b/src/NzbDrone.Core/Indexers/IndexerBase.cs
index 53e921337..66ba9312b 100644
--- a/src/NzbDrone.Core/Indexers/IndexerBase.cs
+++ b/src/NzbDrone.Core/Indexers/IndexerBase.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentValidation.Results;
 using NLog;
 using NzbDrone.Common.Http;
@@ -66,16 +67,14 @@ namespace NzbDrone.Core.Indexers
 
         protected TSettings Settings => (TSettings)Definition.Settings;
 
-        public abstract IList<ReleaseInfo> FetchRecent();
-
-        public abstract IList<ReleaseInfo> Fetch(BookSearchCriteria searchCriteria);
-        public abstract IList<ReleaseInfo> Fetch(AuthorSearchCriteria searchCriteria);
+        public abstract Task<IList<ReleaseInfo>> FetchRecent();
+        public abstract Task<IList<ReleaseInfo>> Fetch(BookSearchCriteria searchCriteria);
+        public abstract Task<IList<ReleaseInfo>> Fetch(AuthorSearchCriteria searchCriteria);
         public abstract HttpRequest GetDownloadRequest(string link);
 
         protected virtual IList<ReleaseInfo> CleanupReleases(IEnumerable<ReleaseInfo> releases)
         {
             var result = releases.DistinctBy(v => v.Guid).ToList();
-            var settings = Definition.Settings as IIndexerSettings;
 
             result.ForEach(c =>
             {
@@ -94,7 +93,7 @@ namespace NzbDrone.Core.Indexers
 
             try
             {
-                Test(failures);
+                Test(failures).GetAwaiter().GetResult();
             }
             catch (Exception ex)
             {
@@ -105,7 +104,7 @@ namespace NzbDrone.Core.Indexers
             return new ValidationResult(failures);
         }
 
-        protected abstract void Test(List<ValidationFailure> failures);
+        protected abstract Task Test(List<ValidationFailure> failures);
 
         public override string ToString()
         {
diff --git a/src/NzbDrone.Core/Indexers/Newznab/Newznab.cs b/src/NzbDrone.Core/Indexers/Newznab/Newznab.cs
index 3a58b1efd..43d194976 100644
--- a/src/NzbDrone.Core/Indexers/Newznab/Newznab.cs
+++ b/src/NzbDrone.Core/Indexers/Newznab/Newznab.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentValidation.Results;
 using NLog;
 using NzbDrone.Common.Extensions;
@@ -92,9 +93,10 @@ namespace NzbDrone.Core.Indexers.Newznab
             return settings;
         }
 
-        protected override void Test(List<ValidationFailure> failures)
+        protected override async Task Test(List<ValidationFailure> failures)
         {
-            base.Test(failures);
+            await base.Test(failures);
+
             if (failures.HasErrors())
             {
                 return;
diff --git a/src/NzbDrone.Core/Indexers/RssSyncService.cs b/src/NzbDrone.Core/Indexers/RssSyncService.cs
index 8f4a07a04..46e0c0707 100644
--- a/src/NzbDrone.Core/Indexers/RssSyncService.cs
+++ b/src/NzbDrone.Core/Indexers/RssSyncService.cs
@@ -1,4 +1,5 @@
 using System.Linq;
+using System.Threading.Tasks;
 using NLog;
 using NzbDrone.Common.Instrumentation.Extensions;
 using NzbDrone.Core.DecisionEngine;
@@ -39,16 +40,16 @@ namespace NzbDrone.Core.Indexers
             _logger = logger;
         }
 
-        private ProcessedDecisions Sync()
+        private async Task<ProcessedDecisions> Sync()
         {
             _logger.ProgressInfo("Starting RSS Sync");
 
-            var rssReleases = _rssFetcherAndParser.Fetch();
+            var rssReleases = await _rssFetcherAndParser.Fetch();
             var pendingReleases = _pendingReleaseService.GetPending();
 
             var reports = rssReleases.Concat(pendingReleases).ToList();
             var decisions = _downloadDecisionMaker.GetRssDecision(reports);
-            var processed = _processDownloadDecisions.ProcessDecisions(decisions);
+            var processed = await _processDownloadDecisions.ProcessDecisions(decisions);
 
             var message = string.Format("RSS Sync Completed. Reports found: {0}, Reports grabbed: {1}", reports.Count, processed.Grabbed.Count);
 
@@ -64,7 +65,7 @@ namespace NzbDrone.Core.Indexers
 
         public void Execute(RssSyncCommand message)
         {
-            var processed = Sync();
+            var processed = Sync().GetAwaiter().GetResult();
             var grabbedOrPending = processed.Grabbed.Concat(processed.Pending).ToList();
 
             _eventAggregator.PublishEvent(new RssSyncCompleteEvent(processed));
diff --git a/src/NzbDrone.Core/Indexers/Torznab/Torznab.cs b/src/NzbDrone.Core/Indexers/Torznab/Torznab.cs
index b0fc15d02..e81ef6b82 100644
--- a/src/NzbDrone.Core/Indexers/Torznab/Torznab.cs
+++ b/src/NzbDrone.Core/Indexers/Torznab/Torznab.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using FluentValidation.Results;
 using NLog;
 using NzbDrone.Common.Extensions;
@@ -69,9 +70,10 @@ namespace NzbDrone.Core.Indexers.Torznab
             return settings;
         }
 
-        protected override void Test(List<ValidationFailure> failures)
+        protected override async Task Test(List<ValidationFailure> failures)
         {
-            base.Test(failures);
+            await base.Test(failures);
+
             if (failures.HasErrors())
             {
                 return;
diff --git a/src/NzbDrone.Host/Bootstrap.cs b/src/NzbDrone.Host/Bootstrap.cs
index f3a5b97e6..99b2174a1 100644
--- a/src/NzbDrone.Host/Bootstrap.cs
+++ b/src/NzbDrone.Host/Bootstrap.cs
@@ -176,7 +176,7 @@ namespace NzbDrone.Host
                     });
                     builder.ConfigureKestrel(serverOptions =>
                     {
-                        serverOptions.AllowSynchronousIO = true;
+                        serverOptions.AllowSynchronousIO = false;
                         serverOptions.Limits.MaxRequestBodySize = null;
                     });
                     builder.UseStartup<Startup>();
diff --git a/src/Readarr.Api.V1/Indexers/ReleaseController.cs b/src/Readarr.Api.V1/Indexers/ReleaseController.cs
index f8e8cee67..0671b0ef8 100644
--- a/src/Readarr.Api.V1/Indexers/ReleaseController.cs
+++ b/src/Readarr.Api.V1/Indexers/ReleaseController.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using FluentValidation;
 using Microsoft.AspNetCore.Mvc;
 using NLog;
@@ -62,7 +63,7 @@ namespace Readarr.Api.V1.Indexers
         }
 
         [HttpPost]
-        public ActionResult<ReleaseResource> Create(ReleaseResource release)
+        public async Task<ActionResult<ReleaseResource>> DownloadRelease(ReleaseResource release)
         {
             ValidateResource(release);
 
@@ -123,7 +124,7 @@ namespace Readarr.Api.V1.Indexers
                     throw new NzbDroneClientException(HttpStatusCode.NotFound, "Unable to parse books in the release");
                 }
 
-                _downloadService.DownloadReport(remoteBook);
+                await _downloadService.DownloadReport(remoteBook);
             }
             catch (ReleaseDownloadException ex)
             {
@@ -135,26 +136,26 @@ namespace Readarr.Api.V1.Indexers
         }
 
         [HttpGet]
-        public List<ReleaseResource> GetReleases(int? bookId, int? authorId)
+        public async Task<List<ReleaseResource>> GetReleases(int? bookId, int? authorId)
         {
             if (bookId.HasValue)
             {
-                return GetBookReleases(int.Parse(Request.Query["bookId"]));
+                return await GetBookReleases(int.Parse(Request.Query["bookId"]));
             }
 
             if (authorId.HasValue)
             {
-                return GetAuthorReleases(int.Parse(Request.Query["authorId"]));
+                return await GetAuthorReleases(int.Parse(Request.Query["authorId"]));
             }
 
-            return GetRss();
+            return await GetRss();
         }
 
-        private List<ReleaseResource> GetBookReleases(int bookId)
+        private async Task<List<ReleaseResource>> GetBookReleases(int bookId)
         {
             try
             {
-                var decisions = _releaseSearchService.BookSearch(bookId, true, true, true);
+                var decisions = await _releaseSearchService.BookSearch(bookId, true, true, true);
                 var prioritizedDecisions = _prioritizeDownloadDecision.PrioritizeDecisions(decisions);
 
                 return MapDecisions(prioritizedDecisions);
@@ -166,11 +167,11 @@ namespace Readarr.Api.V1.Indexers
             }
         }
 
-        private List<ReleaseResource> GetAuthorReleases(int authorId)
+        private async Task<List<ReleaseResource>> GetAuthorReleases(int authorId)
         {
             try
             {
-                var decisions = _releaseSearchService.AuthorSearch(authorId, false, true, true);
+                var decisions = await _releaseSearchService.AuthorSearch(authorId, false, true, true);
                 var prioritizedDecisions = _prioritizeDownloadDecision.PrioritizeDecisions(decisions);
 
                 return MapDecisions(prioritizedDecisions);
@@ -182,9 +183,9 @@ namespace Readarr.Api.V1.Indexers
             }
         }
 
-        private List<ReleaseResource> GetRss()
+        private async Task<List<ReleaseResource>> GetRss()
         {
-            var reports = _rssFetcherAndParser.Fetch();
+            var reports = await _rssFetcherAndParser.Fetch();
             var decisions = _downloadDecisionMaker.GetRssDecision(reports);
             var prioritizedDecisions = _prioritizeDownloadDecision.PrioritizeDecisions(decisions);
 
@@ -195,6 +196,7 @@ namespace Readarr.Api.V1.Indexers
         {
             var resource = base.MapDecision(decision, initialWeight);
             _remoteBookCache.Set(GetCacheKey(resource), decision.RemoteBook, TimeSpan.FromMinutes(30));
+
             return resource;
         }
 
diff --git a/src/Readarr.Api.V1/Indexers/ReleasePushController.cs b/src/Readarr.Api.V1/Indexers/ReleasePushController.cs
index 1e3ceb9d7..3c8158fc4 100644
--- a/src/Readarr.Api.V1/Indexers/ReleasePushController.cs
+++ b/src/Readarr.Api.V1/Indexers/ReleasePushController.cs
@@ -58,7 +58,7 @@ namespace Readarr.Api.V1.Indexers
             lock (PushLock)
             {
                 decisions = _downloadDecisionMaker.GetRssDecision(new List<ReleaseInfo> { info });
-                _downloadDecisionProcessor.ProcessDecisions(decisions);
+                _downloadDecisionProcessor.ProcessDecisions(decisions).GetAwaiter().GetResult();
             }
 
             var firstDecision = decisions.FirstOrDefault();
diff --git a/src/Readarr.Api.V1/Queue/QueueActionController.cs b/src/Readarr.Api.V1/Queue/QueueActionController.cs
index df7edf62a..52bcdcd11 100644
--- a/src/Readarr.Api.V1/Queue/QueueActionController.cs
+++ b/src/Readarr.Api.V1/Queue/QueueActionController.cs
@@ -1,3 +1,4 @@
+using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc;
 using NzbDrone.Core.Download;
 using NzbDrone.Core.Download.Pending;
@@ -20,7 +21,7 @@ namespace Readarr.Api.V1.Queue
         }
 
         [HttpPost("grab/{id:int}")]
-        public object Grab(int id)
+        public async Task<object> Grab(int id)
         {
             var pendingRelease = _pendingReleaseService.FindPendingQueueItem(id);
 
@@ -29,13 +30,14 @@ namespace Readarr.Api.V1.Queue
                 throw new NotFoundException();
             }
 
-            _downloadService.DownloadReport(pendingRelease.RemoteBook);
+            await _downloadService.DownloadReport(pendingRelease.RemoteBook);
 
             return new { };
         }
 
         [HttpPost("grab/bulk")]
-        public object Grab([FromBody] QueueBulkResource resource)
+        [Consumes("application/json")]
+        public async Task<object> Grab([FromBody] QueueBulkResource resource)
         {
             foreach (var id in resource.Ids)
             {
@@ -46,7 +48,7 @@ namespace Readarr.Api.V1.Queue
                     throw new NotFoundException();
                 }
 
-                _downloadService.DownloadReport(pendingRelease.RemoteBook);
+                await _downloadService.DownloadReport(pendingRelease.RemoteBook);
             }
 
             return new { };