Today WSUS stopped working because the Windows Internal Database service was stopped. The error when I tried to start the Windows Internal Database service was:
Windows could not start the Windows Internal Database service on local computer… Log on failed
Usually when you can’t start a service because of a log on failure, it means that the user account used to start the service either doesn’t have permission or the password is wrong.
To fix this, I gave the user account (or more specifically NT SERVICE\ALL SERVICES) the Log on as Service privilege in the local policy.