diff --git a/Code/Mantid/MantidPlot/src/ApplicationWindow.cpp b/Code/Mantid/MantidPlot/src/ApplicationWindow.cpp
index 2deb05285913cea42ca0ac192ad65e5ac70fd29a..9fb04d6f4326d41dfaf598f8ae46315692e2f66f 100644
--- a/Code/Mantid/MantidPlot/src/ApplicationWindow.cpp
+++ b/Code/Mantid/MantidPlot/src/ApplicationWindow.cpp
@@ -9492,6 +9492,7 @@ void ApplicationWindow::closeEvent( QCloseEvent* ce )
   {
     icatsearch->disconnect();
     delete icatsearch;
+    icatsearch = NULL;
   }
 
   if( scriptingWindow )