27 August 2014

How to Remove Orphaned Domain Controller from Active Directory

When you try to remove a domain controller from your Active Directory domain by using Dcpromo.exe and fail, or when you began to promote a member server to be a Domain Controller and failed (the reasons for your failure are not important for the scope of this article), you will be left with remains of the DCs object in the Active Directory. As part of a successful demotion process, the Dcpromo wizard removes the configuration data for the domain controller from Active Directory, but as noted above, a failed Dcpromo attempt might leave these objects in place which is called orphaned objects.

Below are the steps to remove Orphaned Domain Controller from Active Directory. This will help to improve the health and performance of Active Directory and clean up the mess of Active Directory.

To clean up metadata

  1. At the command line, type Ntdsutil and press ENTER.
  2. At the Ntdsutil: prompt, type metadata cleanup and press Enter.
  3. At the metadata cleanup: prompt type connections and press Enter.
  4. At the server connections: prompt, type connect to server <server name>, where <server name> is the domain controller (any functional domain controller in the same domain) from which you plan to clean up the metadata of the failed domain controller. Press Enter.
  5. Type quit (q) and press Enter to return you to the metadata cleanup: prompt.
  6. Type select operation target and press Enter.
  7. Type list domains and press Enter. This lists all domains in the forest with a number associated with each.
  8. Type select domain <number>, where <number> is the number corresponding to the domain in which the failed server was located. Press Enter.
  9. Type list sites and press Enter.
  10. Type select site <number> where <number> refers to the number of the site in which the domain controller was a member. Press Enter.
  11. Type list servers in site and press Enter. This will list all servers in that site with a corresponding number.
  12. Type select server <number> and press Enter, where <number> refers to the domain controller to be removed.
  13. Type quit (q) and press Enter. The Metadata cleanup menu is displayed.
  14. Type remove selected server and press Enter.

You will receive a warning message. Read it, and if you agree, press yes.

At this point, Active Directory confirms that the domain controller was removed successfully. If you receive an error that the object could not be found, Active Directory might have already removed from the domain controller.

  1. Type quit (q) and press Enter until you return to the command prompt.

To remove the failed server object from the sites

  1. In Active Directory Sites and Services, expand the appropriate site.
  2. Delete the server object associated with the failed domain controller

To remove the failed server object from the domain controllers container

  1. In Active Directory Users and Computers, expand the domain controllers container.
  2. Delete the computer object associated with the failed domain controller.

Windows Server 2003 AD might display a new type of question window, asking you if you want to delete the server object without performing a DCPROMO operation (which, of course, you cannot perform, otherwise you wouldn’t be reading this article, would you…) Select “This DC is permanently offline…” and click on the Delete button. AD will display another confirmation window. If you’re sure that you want to delete the failed object, click Yes.

To remove the failed server object from DNS

  1. In the DNS snap-in, expand the zone that is related to the domain from where the server has been removed.
  2. Remove the CNAME record in the _msdcs.root domain of forest zone in DNS. You should also delete the HOSTNAME and other DNS records.
  3. If you have reverse lookup zones, also remove the server from these zones.

Other considerations

Also, consider the following:

  • If the removed domain controller was a global catalog server, evaluate whether application servers that pointed to the offline global catalog server must be pointed to a live global catalog server.
  • If the removed DC was a global catalog server, evaluate whether an additional global catalog must be promoted to the address site, the domain, or the forest global catalog load.
  • If the removed DC was a Flexible Single Master Operation (FSMO) role holder, relocate those roles to a live DC.
  • If the removed DC was a DNS server, update the DNS client configuration on all member workstations, member servers, and other DCs that might have used this DNS server for name resolution. If it is required, modify the DHCP scope to reflect the removal of the DNS server.
  • If the removed DC was a DNS server, update the Forwarder settings and the Delegation settings on any other DNS servers that might have pointed to the removed DC for name resolution.
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