diff --git a/PrinterControls/TerminalWindow/PrinterOutputCache.cs b/PrinterControls/TerminalWindow/PrinterOutputCache.cs
index 6866e56f1..89c1691b8 100644
--- a/PrinterControls/TerminalWindow/PrinterOutputCache.cs
+++ b/PrinterControls/TerminalWindow/PrinterOutputCache.cs
@@ -107,7 +107,6 @@ namespace MatterHackers.MatterControl
             StringEventArgs eventArgs = new StringEventArgs("->" + lineString.Data);
             PrinterLines.Add(eventArgs.Data);
             OnHasChanged(eventArgs);
-            OnHasChanged(eventArgs);
         }
 
         void Instance_ConnectionFailed(object sender, EventArgs e)