I'm running a Win2000 native AD with 2 DCs (DC1 and DC2) with Exchange 2000. I want to upgrade to Win2003, so I moved all FSMO roles to DC1, demoted DC2 and did the /forestprep and /domainprep. Then I did an in-place upgrade of DC1 that seemed to go fine. After that I did a clean reinstall of DC2 and ran DCpromo. DCpromo did some stuff, then replicated a batch (approx 1500 objects) and begun replicating a second batch (approx 8500 objects.) However, when it hit 4500 objects I got this error: "...could not replicate because of an active directory mismatch between the servers involved."
In the DC2 directory eventlog (which dcpromo has created) I got approximately 45 yellows saying: "Internal event: The following schema class has a superclass that is not valid". Several of these seems to be exchange related.
Everything seems to run fine and dcdiag reports that all is well. What can I do to remedy this mismatch?
If you continue to get these events you may want to rebuild DC2. It sounds like the removal of DC2 might not have been fully replicated to DC1 prior to your upgrading DC1. In that event, you'll want to DCpromo DC2 once more back down to a member server, and then check Active Directory to ensure it is seen as a member server. That said, if the errors did go away then you can safely ignore the ones you received.