diff --git a/src/Forms/Main.cs b/src/Forms/Main.cs
index 31dade2e4..dad374c15 100644
--- a/src/Forms/Main.cs
+++ b/src/Forms/Main.cs
@@ -13559,10 +13559,14 @@ namespace Nikse.SubtitleEdit.Forms
 
         private void toolStripComboBoxWaveForm_SelectedIndexChanged(object sender, EventArgs e)
         {
-            ComboBoxZoomItem item = toolStripComboBoxWaveForm.SelectedItem as ComboBoxZoomItem;
-            if (item != null)
+            try
             {
-                audioVisualizer.ZoomFactor = item.ZoomFactor;
+                ComboBoxZoomItem item = toolStripComboBoxWaveForm.SelectedItem as ComboBoxZoomItem;
+                if (item != null)
+                    audioVisualizer.ZoomFactor = item.ZoomFactor;
+            }
+            catch
+            { 
             }
         }
 
diff --git a/src/Logic/VideoPlayers/QuartsPlayer.cs b/src/Logic/VideoPlayers/QuartsPlayer.cs
index b272cfd47..eb704a4c0 100644
--- a/src/Logic/VideoPlayers/QuartsPlayer.cs
+++ b/src/Logic/VideoPlayers/QuartsPlayer.cs
@@ -61,7 +61,17 @@ namespace Nikse.SubtitleEdit.Logic.VideoPlayers
 
         public override double Duration
         {
-            get { return _mediaPosition.Duration; }
+            get 
+            {
+                try
+                {
+                    return _mediaPosition.Duration;
+                }
+                catch
+                {
+                    return 0;
+                }
+            }
         }
 
         public override double CurrentPosition
@@ -236,7 +246,7 @@ namespace Nikse.SubtitleEdit.Logic.VideoPlayers
             if (_isPaused == false && _quartzFilgraphManager != null && CurrentPosition >= Duration)
             {
                 _isPaused = true;
-                if (OnVideoEnded != null)
+                if (OnVideoEnded != null && _quartzFilgraphManager != null)
                     OnVideoEnded.Invoke(_quartzFilgraphManager, new EventArgs());
             }
         }