Add 2008 DC to 2003 – domain schema upgrade failed

active-directorydomain-controllerwindows-server-2003windows-server-2008

I'm trying to add the first 2008 R2 DC to an existing 2003 domain (upgraded to 2003 functionality). I've followed the steps from microsoft which are clarified by this post:
2003 DC AD upgrade to 2008 on second server migration plan
While running adprep /forestprep I lost my connection and wasn't able to resume or remote control that session, so I couldn't see the end result of the command.

Rerunning adprep /forestprep indicates that the process has already been completed successfully. After finishing the rest of the steps (/domainprep … and /gpprep, etc), the 2008 server fails on dcpromo. The error message is the same "you need to run forestprep first"

So the situation I'm in is that I can't rerun /forestprep, but my Registry key still reads schemaVer=30. Should I have staged forest upgrades? Any ideas how to get my schema ver to 44 at this point?

Best Answer

You can try running through dcdiag /fix and possibly using the netdiag /fix (might have to download netdiag separately, it's been a while..) from the 2003 DC. After that, try running the /forestprep and /domainprep again