handle no subs setting

MediaBrowser.Server.Implementations/Library/MediaSourceManager.cs

@@ -17,6 +17,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using CommonIO;
 using MediaBrowser.Common.IO;
+using MediaBrowser.Model.Configuration;
 
 namespace MediaBrowser.Server.Implementations.Library
 {
@@ -276,7 +277,7 @@ namespace MediaBrowser.Server.Implementations.Library
 
         private void SetDefaultSubtitleStreamIndex(MediaSourceInfo source, UserItemData userData, User user)
         {
-            if (userData.SubtitleStreamIndex.HasValue && user.Configuration.RememberSubtitleSelections)
+            if (userData.SubtitleStreamIndex.HasValue && user.Configuration.RememberSubtitleSelections && user.Configuration.SubtitleMode != SubtitlePlaybackMode.None)
             {
                 var index = userData.SubtitleStreamIndex.Value;
                 // Make sure the saved index is still valid