diff --git a/src/NzbDrone.Common.Test/ProcessProviderTests.cs b/src/NzbDrone.Common.Test/ProcessProviderTests.cs
index b4ea33b7c..913271134 100644
--- a/src/NzbDrone.Common.Test/ProcessProviderTests.cs
+++ b/src/NzbDrone.Common.Test/ProcessProviderTests.cs
@@ -3,6 +3,7 @@ using System.ComponentModel;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
+using System.Threading;
 using FluentAssertions;
 using NUnit.Framework;
 using NzbDrone.Common.Model;
@@ -64,12 +65,30 @@ namespace NzbDrone.Common.Test
         }
 
         [Test]
-        public void Should_be_able_to_start_process()
+        public void should_be_able_to_start_process()
+        {
+            var process = StartDummyProcess();
+
+            var check = Subject.GetProcessById(process.Id);
+            check.Should().NotBeNull();
+
+            process.Refresh();
+            process.HasExited.Should().BeFalse();
+
+            process.Kill();
+            process.WaitForExit();
+            process.HasExited.Should().BeTrue();
+        }
+
+        [Test]
+        [Platform(Exclude="MacOsX")]
+        [Retry(3)]
+        public void exists_should_find_running_process()
         {
             var process = StartDummyProcess();
 
             Subject.Exists(DummyApp.DUMMY_PROCCESS_NAME).Should()
-                   .BeTrue("excepted one dummy process to be already running");
+                   .BeTrue("expected one dummy process to be already running");
 
             process.Kill();
             process.WaitForExit();
@@ -126,8 +145,8 @@ namespace NzbDrone.Common.Test
             }
         }
 
-
         [Test]
+        [Platform(Exclude="MacOsX")]
         public void kill_all_should_kill_all_process_with_name()
         {
             var dummy1 = StartDummyProcess();
@@ -141,15 +160,30 @@ namespace NzbDrone.Common.Test
 
         private Process StartDummyProcess()
         {
+            var processStarted = new ManualResetEventSlim();
+
             var path = Path.Combine(TestContext.CurrentContext.TestDirectory, DummyApp.DUMMY_PROCCESS_NAME + ".exe");
-            return Subject.Start(path);
+            var process = Subject.Start(path, onOutputDataReceived: (string data) => {
+                    if (data.StartsWith("Dummy process. ID:"))
+                    {
+                        processStarted.Set();
+                    }
+                });
+
+            if (!processStarted.Wait(2000))
+            {
+                Assert.Fail("Failed to start process within 2 sec");
+            }
+
+            return process;
         }
 
         [Test]
+        [Retry(3)]
         public void ToString_on_new_processInfo()
         {
             Console.WriteLine(new ProcessInfo().ToString());
             ExceptionVerification.MarkInconclusive(typeof(Win32Exception));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/NzbDrone.Common.Test/WebClientTests.cs b/src/NzbDrone.Common.Test/WebClientTests.cs
index 9380a4a7a..34a9de418 100644
--- a/src/NzbDrone.Common.Test/WebClientTests.cs
+++ b/src/NzbDrone.Common.Test/WebClientTests.cs
@@ -19,14 +19,20 @@ namespace NzbDrone.Common.Test
         }
 
         [TestCase("")]
-        [TestCase("http://")]
-        public void DownloadString_should_throw_on_error_windows(string url)
+        public void DownloadString_should_throw_on_empty_string(string url)
         {
-            WindowsOnly();
             Assert.Throws<ArgumentException>(() => Subject.DownloadString(url));
             ExceptionVerification.ExpectedWarns(1);
         }
 
+        // .net 4.6.2 throws NotSupportedException instead of ArgumentException here
+        [TestCase("http://")]
+        public void DownloadString_should_throw_on_not_supported_string_windows(string url)
+        {
+            WindowsOnly();
+            Assert.Throws<NotSupportedException>(() => Subject.DownloadString(url));
+            ExceptionVerification.ExpectedWarns(1);
+        }
 
         [TestCase("http://")]
         public void DownloadString_should_throw_on_not_supported_string_mono(string url)
diff --git a/src/NzbDrone.Core.Test/InstrumentationTests/DatabaseTargetFixture.cs b/src/NzbDrone.Core.Test/InstrumentationTests/DatabaseTargetFixture.cs
index 098fd5f96..6608bd42f 100644
--- a/src/NzbDrone.Core.Test/InstrumentationTests/DatabaseTargetFixture.cs
+++ b/src/NzbDrone.Core.Test/InstrumentationTests/DatabaseTargetFixture.cs
@@ -40,7 +40,7 @@ namespace NzbDrone.Core.Test.InstrumentationTests
         {
             _logger.Info(_uniqueMessage);
 
-            Thread.Sleep(600);
+            Thread.Sleep(1000);
 
             StoredModel.Message.Should().Be(_uniqueMessage);
             VerifyLog(StoredModel, LogLevel.Info);
@@ -57,7 +57,7 @@ namespace NzbDrone.Core.Test.InstrumentationTests
 
             _logger.Info(message);
 
-            Thread.Sleep(600);
+            Thread.Sleep(1000);
 
             StoredModel.Message.Should().HaveLength(message.Length);
             StoredModel.Message.Should().Be(message);
@@ -76,7 +76,7 @@ namespace NzbDrone.Core.Test.InstrumentationTests
                 _logger.Info(Guid.NewGuid());
             }
 
-            Thread.Sleep(600);
+            Thread.Sleep(1000);
 
             MapRepository.Instance.EnableTraceLogging = true;
         }
@@ -88,7 +88,7 @@ namespace NzbDrone.Core.Test.InstrumentationTests
 
             _logger.Error(ex, _uniqueMessage);
 
-            Thread.Sleep(600);
+            Thread.Sleep(1000);
 
             VerifyLog(StoredModel, LogLevel.Error);
             StoredModel.Message.Should().Be(_uniqueMessage + ": " + ex.Message);
@@ -106,7 +106,7 @@ namespace NzbDrone.Core.Test.InstrumentationTests
 
             _logger.Error(ex, _uniqueMessage);
 
-            Thread.Sleep(600);
+            Thread.Sleep(1000);
 
             StoredModel.Message.Should().Be(ex.Message);
 
@@ -121,7 +121,7 @@ namespace NzbDrone.Core.Test.InstrumentationTests
             var epFile = new MovieFile();
             _logger.Debug("File {0} no longer exists on disk. removing from database.", epFile.RelativePath);
 
-            Thread.Sleep(600);
+            Thread.Sleep(1000);
 
             epFile.RelativePath.Should().BeNull();
         }
diff --git a/src/NzbDrone.Core.Test/ValidationTests/SystemFolderValidatorFixture.cs b/src/NzbDrone.Core.Test/ValidationTests/SystemFolderValidatorFixture.cs
index 6d9e6f2c5..3a836bfad 100644
--- a/src/NzbDrone.Core.Test/ValidationTests/SystemFolderValidatorFixture.cs
+++ b/src/NzbDrone.Core.Test/ValidationTests/SystemFolderValidatorFixture.cs
@@ -7,6 +7,7 @@ using NzbDrone.Core.Test.Framework;
 using NzbDrone.Core.Movies;
 using NzbDrone.Core.Validation.Paths;
 using NzbDrone.Test.Common;
+using NzbDrone.Common.EnvironmentInfo;
 
 namespace NzbDrone.Core.Test.ValidationTests
 {
@@ -52,8 +53,9 @@ namespace NzbDrone.Core.Test.ValidationTests
         {
             MonoOnly();
 
+            var bin = OsInfo.IsOsx ? "/System" : "/bin";
             var movie = Builder<Movie>.CreateNew()
-                                        .With(s => s.Path = "/bin")
+                                        .With(s => s.Path = bin)
                                         .Build();
 
             _validator.Validate(movie).IsValid.Should().BeFalse();
@@ -64,9 +66,10 @@ namespace NzbDrone.Core.Test.ValidationTests
         {
             MonoOnly();
 
+            var bin = OsInfo.IsOsx ? "/System" : "/bin";
             var movie = Builder<Movie>.CreateNew()
-                                        .With(s => s.Path = "/bin/test")
-                                        .Build();
+                .With(s => s.Path = Path.Combine(bin, "test"))
+                .Build();
 
             _validator.Validate(movie).IsValid.Should().BeFalse();
         }