Index: /trunk/src/VBox/Additions/common/VBoxGuest/VBoxGuest.cpp
===================================================================
--- /trunk/src/VBox/Additions/common/VBoxGuest/VBoxGuest.cpp	(revision 70225)
+++ /trunk/src/VBox/Additions/common/VBoxGuest/VBoxGuest.cpp	(revision 70226)
@@ -4236,6 +4236,10 @@
 bool VGDrvCommonIsOurIRQ(PVBOXGUESTDEVEXT pDevExt)
 {
+    VMMDevMemory volatile *pVMMDevMemory;
+    bool fOurIrq;
+
     RTSpinlockAcquire(pDevExt->EventSpinlock);
-    bool const fOurIrq = pDevExt->pVMMDevMemory->V.V1_04.fHaveEvents;
+    pVMMDevMemory = pDevExt->pVMMDevMemory;
+    fOurIrq = pVMMDevMemory ? pVMMDevMemory->V.V1_04.fHaveEvents : false;
     RTSpinlockRelease(pDevExt->EventSpinlock);
 
@@ -4257,4 +4261,5 @@
     bool                    fMousePositionChanged = false;
     int                     rc                    = 0;
+    VMMDevMemory volatile  *pVMMDevMemory;
     bool                    fOurIrq;
 
@@ -4269,5 +4274,6 @@
      */
     RTSpinlockAcquire(pDevExt->EventSpinlock);
-    fOurIrq = pDevExt->pVMMDevMemory->V.V1_04.fHaveEvents;
+    pVMMDevMemory = pDevExt->pVMMDevMemory;
+    fOurIrq = pVMMDevMemory ? pVMMDevMemory->V.V1_04.fHaveEvents : false;
     if (fOurIrq)
     {