Index: /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIDesktopWidgetWatchdog.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIDesktopWidgetWatchdog.cpp	(revision 60632)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/globals/UIDesktopWidgetWatchdog.cpp	(revision 60633)
@@ -133,5 +133,6 @@
     /* Cleanup existing workers first: */
     foreach (QWidget *pWorker, m_availableGeometryWorkers)
-        pWorker->disconnect();
+        if (pWorker)
+            pWorker->disconnect();
     qDeleteAll(m_availableGeometryWorkers);
     m_availableGeometryWorkers.clear();
@@ -209,5 +210,6 @@
     /* Cleanup existing workers finally: */
     foreach (QWidget *pWorker, m_availableGeometryWorkers)
-        pWorker->disconnect();
+        if (pWorker)
+            pWorker->disconnect();
     qDeleteAll(m_availableGeometryWorkers);
     m_availableGeometryWorkers.clear();