Over the weekend, all the administrators of one of my servers lost their privileges. Nobody can do administrative tasks on the server, such as use Server Manager. Only the service account is still able to remote into the server.
What could cause this? Is it possible that re-naming the local Administrator user group could have caused this? (I don't think I re-named the administrator group, but it is possible I did so accidentally).
Server is Windows Server 2008 R2