Index: /trunk/src/VBox/VMM/VMMR3/TM.cpp
===================================================================
--- /trunk/src/VBox/VMM/VMMR3/TM.cpp	(revision 68019)
+++ /trunk/src/VBox/VMM/VMMR3/TM.cpp	(revision 68020)
@@ -1178,4 +1178,23 @@
     pVM->tm.s.fParavirtTscEnabled = false;
 
+    /*
+     * Reset TSC to avoid a windows 8 bug (see @bugref{8926}).
+     */
+    VM_ASSERT_EMT0(pVM);
+    uint64_t offTscRawSrc;
+    if (pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET)
+        offTscRawSrc = SUPReadTsc();
+    else
+    {
+        offTscRawSrc = TMVirtualSyncGetNoCheck(pVM);
+        offTscRawSrc = ASMMultU64ByU32DivByU32(offTscRawSrc, pVM->tm.s.cTSCTicksPerSecond, TMCLOCK_FREQ_VIRTUAL);
+    }
+    for (VMCPUID iCpu = 0; iCpu < pVM->cCpus; iCpu++)
+    {
+        pVM->aCpus[iCpu].tm.s.offTSCRawSrc   = offTscRawSrc;
+        pVM->aCpus[iCpu].tm.s.u64TSC         = 0;
+        pVM->aCpus[iCpu].tm.s.u64TSCLastSeen = 0;
+    }
+
     TM_UNLOCK_TIMERS(pVM);
 }