Index: /trunk/src/VBox/VMM/VMMAll/PGMAllBth.h
===================================================================
--- /trunk/src/VBox/VMM/VMMAll/PGMAllBth.h	(revision 20063)
+++ /trunk/src/VBox/VMM/VMMAll/PGMAllBth.h	(revision 20064)
@@ -1683,5 +1683,10 @@
 # endif
     SHWPDE          PdeDst   = *pPdeDst;
-    AssertMsg(PdeDst.n.u1Present, ("%p=%llx\n", pPdeDst, (uint64_t)PdeDst.u));
+    if (!PdeDst.n.u1Present)
+    {
+        AssertMsg(pVM->cCPUs > 1, ("%Unexpected missing PDE p=%llx\n", pPdeDst, (uint64_t)PdeDst.u));
+        return VINF_SUCCESS;    /* force the instruction to be executed again. */
+    }
+
     PPGMPOOLPAGE    pShwPage = pgmPoolGetPage(pPool, PdeDst.u & SHW_PDE_PG_MASK);