Index: /trunk/src/VBox/VMM/VMMAll/PGMAllPool.cpp
===================================================================
--- /trunk/src/VBox/VMM/VMMAll/PGMAllPool.cpp	(revision 22737)
+++ /trunk/src/VBox/VMM/VMMAll/PGMAllPool.cpp	(revision 22738)
@@ -2514,4 +2514,8 @@
 #endif
                     }
+#ifdef PGMPOOL_WITH_OPTIMIZED_DIRTY_PT
+                    else
+                        Assert(!pPage->fDirty);
+#endif
                 }
                 /* fall thru */