I’ve been experiencing this issue on and off for ages and I can honestly say its doing my head in. I’ve searched for a solution to this before, but didn’t get anywhere.However, today I found the below

http://social.technet.microsoft.com/Forums/en-US/winserverManagement/thread/d070a094-6894-4288-b9de-52006173cdd0

The long and short of it is http://support.microsoft.com/kb/2466373