I am installing a Server 2012 std.  in a single domain. The current DC is Server 2008 std. When I try to raise the domain functional level to at least 2003 it gives me an error.

I did the save as and viewed the error message.  Apparently some time in the past they had a Server 2000 and active directory still has the entries that is preventing the domain from being raised.  I removed the old server from AD CU and restarted the server.  Still will not let me raise the level, same error.  Do I need to use ADSI edit and remove all the entries also?  What about DNS entries?

Thank you for a rapid answer.

Hi Wade,

Please refer to following KB and check if can help you. (Please back up before all operations. That will help us to avoid unexpected issues.)

How to remove data in Active Directory after an unsuccessful domain controller demotion

In addition, please also use dcdiag command-line tool to verify domain controller health.

If any update, please feel free to let me know.

Hope this helps.

Best regards,

Justin Gu