Index: /trunk/src/VBox/Devices/Audio/AudioMixer.cpp
===================================================================
--- /trunk/src/VBox/Devices/Audio/AudioMixer.cpp	(revision 87855)
+++ /trunk/src/VBox/Devices/Audio/AudioMixer.cpp	(revision 87856)
@@ -323,12 +323,11 @@
         PAUDMIXSINK pSinkToRemove = pSink;
 
+        audioMixerSinkDestroyInternal(pSinkToRemove);
         audioMixerRemoveSinkInternal(pMixer, pSinkToRemove);
 
-        audioMixerSinkDestroyInternal(pSinkToRemove);
-
         RTMemFree(pSinkToRemove);
     }
 
-    pMixer->cSinks = 0;
+    Assert(pMixer->cSinks == 0);
 
     if (pMixer->pszName)
@@ -917,5 +916,6 @@
     }
 
-    if (pSink->pParent->fFlags & AUDMIXER_FLAGS_DEBUG)
+    if (   pSink->pParent
+        && pSink->pParent->fFlags & AUDMIXER_FLAGS_DEBUG)
     {
         DrvAudioHlpFileDestroy(pSink->Dbg.pFile);