Question : Last Domain Contoller Will Not Demote

When I run DCPROMO on the last Windows Server 2003 Domain controller that is left in a domain that I am trying to get rid of, I mark the checkbox on the first screen of the AD wizard indicating that it is the last DC and then go through to the final screen where I start the removal of AD, but then I get an error saying the operation failed because the DC is not the last DC in the domain and the "server has refused to process the request."

When I start over and try to unmark the checkbox on the first screen I get a notice stating that checkbox is unchecked, but there are no other AD domain controllers in this domain that can be contacted. I say OK to this and go on through to the final screen to start the removal of AD, but I now get an error saying the operation failed because a domain controller could not be contacted that have an account for this computer. The message goes on to tell me to make this computer a member of a workgroup and then rejoin the domain before trying demotion (which clearly isn't possible).

Answer : Last Domain Contoller Will Not Demote

Could it be that at some time, a DC died or was removed from the network, without being demoted? Then you'll have to dlear out your AD first:
How to remove data in Active Directory after an unsuccessful domain controller demotion
http://support.microsoft.com/?kbid=216498