Index: /trunk/src/VBox/Main/src-client/GuestCtrlPrivate.cpp
===================================================================
--- /trunk/src/VBox/Main/src-client/GuestCtrlPrivate.cpp	(revision 52980)
+++ /trunk/src/VBox/Main/src-client/GuestCtrlPrivate.cpp	(revision 52981)
@@ -1269,4 +1269,9 @@
 GuestWaitEventBase::~GuestWaitEventBase(void)
 {
+    if (mEventSem != NIL_RTSEMEVENT)
+    {
+        RTSemEventDestroy(mEventSem);
+        mEventSem = NIL_RTSEMEVENT;
+    }
 }