diff --git a/src/NzbDrone.Core/MediaCover/MediaCoverProxy.cs b/src/NzbDrone.Core/MediaCover/MediaCoverProxy.cs
index b8b0cc3a0..fa489171b 100644
--- a/src/NzbDrone.Core/MediaCover/MediaCoverProxy.cs
+++ b/src/NzbDrone.Core/MediaCover/MediaCoverProxy.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Threading.Tasks;
 using NzbDrone.Common.Cache;
+using NzbDrone.Common.Extensions;
 using NzbDrone.Common.Http;
 using NzbDrone.Core.Configuration;
 
@@ -31,6 +32,11 @@ namespace NzbDrone.Core.MediaCover
 
         public string RegisterUrl(string url)
         {
+            if (url.IsNullOrWhiteSpace())
+            {
+                return null;
+            }
+
             var hash = url.SHA256Hash();
 
             _cache.Set(hash, url, TimeSpan.FromHours(24));