Forcing a demotion of a domain controller – server core
I recently installed a 2nd DC on my network and then, due to naming issues, I had to demote it, in order to rename it.
It wouldn’t demote, using the instructions posted on an earlier blog
So it had to be forced
The syntax for running dcpromo, on a server core machine, to force demotion is
dcpromo /unattend /forceremoval /demotefsmo:yes /username:<domain admin> /userdomain:<domain> /password:<DA password> /administratorpassword:<local admin password>
So open up a command prompt and run the dcpromo command with the relevant switches.
dcpromo /unattend /forceremoval /demotefsmo:yes /username:administrator /userdomain:BR /password:BongoBongo/administratorpassword:BungoBungo
and voila the server removed AD and shutdown.
In my case, I then renamed the server, rebooted it and promoted it again using the instructions detailed here
Hope this helps