diff --git a/PartPreviewWindow/GcodeViewBasic.cs b/PartPreviewWindow/GcodeViewBasic.cs
index 52ce0dc97..2d597d6a7 100644
--- a/PartPreviewWindow/GcodeViewBasic.cs
+++ b/PartPreviewWindow/GcodeViewBasic.cs
@@ -145,7 +145,7 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 
                 // we only hook these up to make sure we can regenerate the gcode when we want
                 printItem.SlicingOutputMessage += sliceItem_SlicingOutputMessage;
-                printItem.Done += new EventHandler(sliceItem_Done);
+                printItem.Done += sliceItem_Done;
             }
 
             centerPartPreviewAndControls.AddChild(gcodeDispalyWidget);
@@ -622,6 +622,12 @@ namespace MatterHackers.MatterControl.PartPreviewWindow
 
         void sliceItem_Done(object sender, EventArgs e)
         {
+            // We can add this while we have it open (when we are done loading).
+            // So we need to make sure we only have it added once. This will be ok to run when
+            // not added or when added and will ensure we only have one hook.
+            printItem.SlicingOutputMessage -= sliceItem_SlicingOutputMessage;
+            printItem.Done -= sliceItem_Done;
+
             UiThread.RunOnIdle(CreateAndAddChildren);
             startedSliceFromGenerateButton = false;
         }
diff --git a/PrintQueue/ExportToFolderProcess.cs b/PrintQueue/ExportToFolderProcess.cs
index 835077283..5ff047e95 100644
--- a/PrintQueue/ExportToFolderProcess.cs
+++ b/PrintQueue/ExportToFolderProcess.cs
@@ -101,6 +101,7 @@ namespace MatterHackers.MatterControl.PrintQueue
             PrintItemWrapper sliceItem = (PrintItemWrapper)sender;
 
             sliceItem.Done -= new EventHandler(sliceItem_Done);
+            sliceItem.SlicingOutputMessage -= printItemWrapper_SlicingOutputMessage;
             savedGCodeFileNames.Add(sliceItem.GCodePathAndFileName);
 
             itemCountBeingWorkedOn++;
diff --git a/PrintQueue/PrintQueueItem.cs b/PrintQueue/PrintQueueItem.cs
index 10931edb4..c00ace4b4 100644
--- a/PrintQueue/PrintQueueItem.cs
+++ b/PrintQueue/PrintQueueItem.cs
@@ -279,6 +279,7 @@ namespace MatterHackers.MatterControl.PrintQueue
 
         public override void OnClosed(EventArgs e)
         {
+            PrintItemWrapper.SlicingOutputMessage -= PrintItem_SlicingOutputMessage;
             if (unregisterEvents != null)
             {
                 unregisterEvents(this, null);