Upgrading 2008R2 domain controllers to 2012R2 DCs with mismatched USN's

I've read through other people's Q&A about upgrading from Windows Server 2008R2 to 2012R2 and seem to have the basic upgrade process down.  My unique situation deals with Update Sequence Numbers not matching on our two domain controllers.  I made the mistake of creating a vSphere snapshot on a DC and restoring it a while back.  I found out later that is a no-no but, it was too late.

My question is - do I have to fix the USN mismatch problem before attempting to do an across the wire DC upgrade on two new server VMs?
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the problem is domain controllers suffered with USN rollback (2095 event id  - directory service) cannot replicate with any DC and hence must be demoted

So the question is, do you have only these two DCs which are problematic or you have other DCs as well?

If you have other working DCs, demote these DCs and then promote new version DCs

If these are only two DCs and both in issues, you must restore AD authoritatively / natively  on one of those DC if you have good AD system state backup before this issue occurs, ensure its working fine and then go for new AD version promotion
But obvious, you need to demote other faulty DC
volleyguyAuthor Commented:
Moderator - I replied to Mahesh but, it's not posted.  Did I reply incorrectly?
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volleyguyAuthor Commented:
Sorry for the delay Mahesh.

I actually have three domain controllers and they all don't match each other.  Before I demote, how do I tell which one is the good one and which two are faulty?

I don't know when this happened so, I don't have a good backup of the good DC's system state.
Shaun VermaakTechnical SpecialistCommented:
Keep the one that is running the PDCe role
volleyguyAuthor Commented:
I ended up contacting Microsoft and they checked the registry entry for USN rollback.  The primary DC was the only one that had the registry key marked so, they demoted the primary and re-promotoed it.  It took some time since other areas needed to be checked, such as AD Sites and Services.  Took about 1-1/2 hours to fix.

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volleyguyAuthor Commented:
Suggested solutions did not solve my problem.
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Windows Server 2012

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