My main DC updated last night. It completed the updates, Stalled on 100% with the do not turn off dialogue. Eventually I had to manually restart the server this morning which caused no end of problems with the server freezing solid when you logged in. Finally rebooted it into safe mode and ran scan disk on all drives. I then rebooted all of the servers, logged back in and left it for 10 minutes at which point it gave me a "failure to open security options dialogue" error. Rebooted it again and it seems to be fine.
Nothing showing up in event viewer to say what went wrong either.
Hell of a way to start the day.
Server 2008 64bit edition.