When you demote a domain controller to a member server, the server object remains in the Active Directory Sites and Services snap-in?
The Dcpromo tool does NOT automatically remove the server object because it is a container that may hold child objects that represent configuration data for other services installed on the server.
NOTE: If the server object contains any child object named NTDS Settings, you must use Ntdsutil to remove them before the you delete the server object.
Once you have verified that all services with dependency on the server object have been removed, you can delete the server object:
1. Open Active Directory Sites and Services.
2. Expand the Sites branch.
3. Expand the site that contains the server object you wish to delete.
4. Double-click the Servers container.
5. Right-click the server object and press Delete.
6. Press Yes when you are prompted to confirm the delete action.
NOTE: The deletion will fail if the server contains child objects that have not completed decommissioning.
NOTE: If a message states that the DSA object can NOT be deleted, you may be deleting an active domain controller.
See the following related tips: