By default, when rebooting a server, Windows will wait for 20 seconds for services to shut themselves down, after which Windows will kill the service. For most systems, this "kill timeout" is sufficient but some applications require more time to do a graceful shutdown (e.g. Quest Rapid Recovery is one of them).

You can change this timeout value by adjusting the string value WaitToKillServiceTimeout in the registry, located at:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control

WaitToKillServiceTimeout sets the timeout value in milliseconds. You can change it to whatever you like. For example: for 10 minutes, set the value to 600000.

Note that increasing this value does not mean the server will always take up 10 minutes to shut down. It only means that services will get up to 10 minutes to shut down gracefully before Windows will forcibly shut them down.