This article describes how to remove an orphaned domain and its servers from Active Directory when there is no active domain controller for the domain.
You may need to perform this method, for example, if the only domain controller for a domain has failed with no chance of recovery. Or, if some of the domain controllers were physically removed without being demoted first.
Start the Sites and Servers snap-in in Microsoft Management Console (MMC), and then connect to the Flexible Single Master Operation (FSMO) role holder.
Remove the computer entry for every computer in the orphaned domain.
NOTE: After you delete the computer entries, the computers no longer have access to Active Directory. You cannot give them access again without reinstalling them. If you delete a computer by accident, the only recovery is by performing an authoritative restore of Active Directory.
When there are no more entries for servers or other computers for the orphaned domain, follow the steps in the following Microsoft Knowledge Base article to remove the orphaned domain from Active Directory:
230306 How to Remove Orphaned Domains from Active Directory
NOTE: If you do not remove every domain controller entry for the domain, you receive an error message when you try to remove the domain. The error message is "DsRemoveDomainW-Error 0x2162."