I think it is no problem unless there are are still open handles to the registry. Like some program did a request to open the registry, but it didn't niclye closed it.
There is an tool for this from Microsoft.
Called
This tool will close every open registry handle still left before loggin of or shuting down.
This can also decrease shutdown time, this becouse when you loggof or shutdown, windows try's to close the registry, but this will fail becouse there are still open handlers, and this can take a while sometimes, especialy when there are more then one users-accounts on the system.
With UPHC installed, it first closes all these handles and then continue the loggoff or shutdown.
This software will function as a services, so you don't have to do anything but install it :).
