check item path for null/empty

MediaBrowser.Providers/MediaInfo/FFProbeProvider.cs

@@ -170,12 +170,15 @@ namespace MediaBrowser.Providers.MediaInfo
         }
 
         public bool HasChanged(IHasMetadata item, IDirectoryService directoryService)
+        {
+            if (!string.IsNullOrWhiteSpace(item.Path))
             {
                 var file = directoryService.GetFile(item.Path);
                 if (file != null && file.LastWriteTimeUtc != item.DateModified)
                 {
                     return true;
                 }
+            }
 
             if (item.SupportsLocalMetadata)
             {