Windows Explored

Everyday Windows Desktop Support, Advanced Troubleshooting & Other OS Tidbits

Forcing a System Crash on a Unresponsive PC

Posted by William Diaz on July 20, 2010

This one comes in handy when a Windows based PC experiences a so-called “hard hang” and you need to force it to bug check and produce a dump for debug purposes. From the Windows registry:

  • For USB keyboards go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\kbdhid\Parameters, create a DWORD value named CrashOnCtrlScroll equal to 11
  • For PS/2 keyboards go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\i8042prt\Parameters, create a DWORD value named CrashOnCtrlScroll equal to 1

You will need to reboot afterwards. A crash can now be initiated by holding down the right CTRL key and pressing the Scroll Lock key twice.

Some laptop keyboards do not have a scroll lock key and you will need to find the substitute (usually the fn key). Alternatively, to workaround this, see this MSDN link for how to setup alternate key combinations: In my case, I have no function key as a substitute on my laptop so I have also defined right Ctrl+BackSpace x2. You will need to obtain the hex code (scancode table) of the key you will be using for the for the Dump2Key DWORD2:

When you manually crash Windows, the dump will tell you this after opening with WinDbg. It is your job to find the culprit in the stack output or by digging deeper into the dump.

1Windows XP does not support this means of crashing the OS via a USB keyboard, only Win7, Server 2008, and Server 2003 SP2 or SP1 with Hotfix 244139 and Vista SP1 with Hotifx 971284. You can also use the Dump Configurator from CodePlex here.

2Note, you will need to disable the CrashOnCtrlScroll DWORD created above for this to work by changing the value to 0 or deleting it.


One Response to “Forcing a System Crash on a Unresponsive PC”

  1. […] Posted by William Diaz on May 7, 2012 I recently put together a quad core system from parts my brother was retiring from his home system. Soon after getting everything up and running, the new system would sometimes hard hang while working via VPN. A hard hang is when the OS becomes completely unresponsive but is still running. I had earlier prepared myself for the next instance of this encounter by enabling CrashOnCtrlScroll in the Windows registry so that the next time it happened I could manually crash the system from the keyboard and examine the memory dump with WinDbg for signs of the responsible culprit. You can read about how to enable this option in this earlier blog Forcing a System Crash on an Unresponsive PC. […]

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