How Windows Shuts Down

Hi my name is Bryan,  I'm a escalation engineer on the Microsoft CPR platforms team.   A common problem scenario involves shutting down Windows. When troubleshooting problems during shut down we have to look at the Winlogon.exe process which can be tricky and must be done correctly.

Troubleshooting Techniques

Common Settings

Settings that would affect how Windows shuts down are mostly in HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon, and are documented thoroughly at http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/regentry/12314.mspx. The setting to really pay attention is:

DisableCAD (REG_DWORD). When set to 1 the GINA will bypass the Ctrl-Alt-Del dialog and go straight to the logon prompt. The system cannot be shutdown when the logon prompt at the console is displayed.

Another common setting that is sometimes needed for security reasons is in HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management.

ClearPageFileAtShutdown (REG_DWORD). When set to 1 the memory manager will clear the paging file on shutdown. If the paging file is large this can significantly the time it takes for the system to shut down.

Winlogon Event Notification

Prior to Windows Vista/2008 Server, Winlogon Notification Packages can be used to reliably monitor the state of Winlogon. These are simple export DLLs that are registered with entry points for each event monitored by the package. Winlogon explicitly calls these entry points when a specific event occurs. Each package handles the notification within the context of the Winlogon process. Keep in mind that a bug in a notification package can cause problems in Winlogon and render the system inaccessible. You can find more information about Winlogon Notification Packages at