I have a small network with a single domain controller, running Windows Server 2008 R2. All was going well until just now.
I had previously had a Windows Server 2003 DC. I demoted it to a workstation and promoted the new 2008 R2 to a DC successfully and used it like that for a couple weeks.
However, to completely migrate everything to the new server it had to get the name of the old server - 'SERVER'. I followed the instructions on http://www.petri.co.il/rename-windows-server-2008-domain-controllers.htm but after step two it told me "Active Directory Domain Services already contain a Computer Account or a Server Object with the specified name: SERVER (blah blah, remove them, account already exists)".
In my infinite wisdom, I decided to reboot the 2008 R2 box. Now I am getting all sorts of errors about not being able to contact the domain security controller. I've also noted that in adsiedit.msc that it lists the server in OU=Domain Controllers as "CN=OLDNAME".
I'm not really sure where to go from here. Unfortunately, I didn't expect this to blow up on me so I don't have a backup to just swap back to.
Renaming the new server back to the original name with
netdom said that it had failed because it couldn't contact the domain, but it had actually succeeded - the System control panel where it lists the computer name contained the message about needing to restart to get the new computer name. After a reboot, it is now working again (hooray, at least I'm not worse off than before).
I took a poke around in Active Directory Sites & Services and it seems the old server is still listed as an object. (It was not listed under Users & Computers with its old name). I'm going to delete it since there is currently no computer on the network with that name and re-try the renaming tutorial I linked from above.