diff --git a/effects/coverswitch.cpp b/effects/coverswitch.cpp
index b7369a1990..de232cc4a5 100644
--- a/effects/coverswitch.cpp
+++ b/effects/coverswitch.cpp
@@ -101,6 +101,8 @@ void CoverSwitchEffect::prePaintScreen( ScreenPrePaintData& data, int time )
                 (dynamicThumbnails && effects->currentTabBoxWindowList().size() >= thumbnailWindows)) )
                 calculateItemSizes();
             }
+        if( effects->currentTabBoxWindow() == NULL )
+            abort();
         }
     effects->prePaintScreen(data, time);
     }
@@ -1476,5 +1478,22 @@ void CoverSwitchEffect::windowInputMouseEvent( Window w, QEvent* e )
         }
     }
 
+void CoverSwitchEffect::abort()
+    {
+    effects->unrefTabBox();
+    effects->setActiveFullScreenEffect( 0 );
+    effects->destroyInputWindow( input );
+    mActivated = false;
+    stop = false;
+    stopRequested = false;
+    effects->addRepaintFull();
+    if( thumbnails && (!dynamicThumbnails ||
+            (dynamicThumbnails && effects->currentTabBoxWindowList().size() >= thumbnailWindows)) )
+        {
+        qDeleteAll( windows );
+        windows.clear();
+        }
+    }
+
 
 } // namespace
diff --git a/effects/coverswitch.h b/effects/coverswitch.h
index 1ee04e6dfb..3014ed386f 100644
--- a/effects/coverswitch.h
+++ b/effects/coverswitch.h
@@ -58,6 +58,7 @@ class CoverSwitchEffect
         void paintWindowCover( EffectWindow* w, bool reflectedWindow, WindowPaintData& data );
         void paintFrontWindow( EffectWindow* frontWindow, int width, int leftWindows, int rightWindows, bool reflectedWindow  );
         void paintWindows( QList< EffectWindow* >* windows, bool left, bool reflectedWindows, EffectWindow* additionalWindow = NULL );
+        void abort();
         // thumbnail bar
         class ItemInfo;
         void calculateFrameSize();