Hi,
You can follow these steps-
If a Domain Controller that no longer exists in Active Directory is still showing up in search results, you can use the Active Directory Sites and Services snap-in to remove it. Here are the steps to do this:
1. Open the Active Directory Sites and Services snap-in on a Domain Controller in the same domain.
2. In the left pane, expand the Sites container and then expand the container for the site where the removed Domain Controller was located.
3. In the left pane, expand the Servers container and then expand the container for the removed Domain Controller.
4. In the left pane, right-click on the NTDS Settings object for the removed Domain Controller and select Delete.
5. Confirm that you want to delete the object by clicking Yes.
6. Close the Active Directory Sites and Services snap-in.
Another method you can use to remove a Domain Controller from AD is by using the ntdsutil command-line tool, here's an example of how to use it:
1. Open the Command Prompt as an administrator
2. Type the following command to enter Ntdsutil:
ntdsutil
3. Type the following command to enter the metadata cleanup mode:
metadata cleanup
4. Type the following command to list all the domain controllers:
connections
5. Type the following command to select the domain controller that you want to remove:
select operation target
6. Type the following command to remove the selected domain controller:
remove selected server
7. Type the following command to quit the Ntdsutil:
quit
Please note that, before you proceed with any of the above steps, make sure that you have a good backup of your AD and make sure that you understand the effect of removing a domain controller on your domain.
Thanks
