is it safe to re-promote a failed dc

Had a failed DC that has been forcedremoved...

Is it safe to dcpromo it back into the domain?

It was the FSMO role holder and all those roles have been seized by another dc, now the failed dc is back working and I would like to just re-promote it without installing the OS.

It has been offline for 3 days, and all the metadata has been cleaned up on the new dc.

Thanks in advance
Who is Participating?

Improve company productivity with a Business Account.Sign Up

Glen KnightConnect With a Mentor Commented:
It is always recommended that if you had to seize the FSMO roles that the server should be flattened and rebuilt.

However, from my experience I can say that I have not known this to be a problem, if it doesn't currently have Active Directory on it then you should be able to re-promote it to a DC.

As I said though it is recommended that it be flattened and rebuilt.
It's safe (like it will not kill you ;). Do you plan to reuse the name and IP?
Sure, If you must avoid the reimage.
Get 10% Off Your First Squarespace Website

Ready to showcase your work, publish content or promote your business online? With Squarespace’s award-winning templates and 24/7 customer service, getting started is simple. Head to and use offer code ‘EXPERTS’ to get 10% off your first purchase.

Glen KnightCommented:
Mike KlineConnect With a Mentor Commented:
Like demazter said you won't go wrong with flatten/rebuild but if you have done the metadata cleanup and made sure the cleanup has replicated and there are no remnants left you should be fine to to join it back up and repromote.

You can also see this link about halfway down for steps


durango099Author Commented:
Thanks for the input-

I am going to backup system state on the current DC, and then attempt to dcpromo the old DC back into the domain using the same name and IP.

Next step would be to transfer the roles back to the failed DC after replaction of AD.

Will run the first attempt tomorrow night (Monday) and report the results.

durango099Author Commented:
The DCPROMO seems to have gone far anyway

Is there a good way to tell if the DC's have replicated?

I have added the GC flag to the failed DC, and once I know the replication is working what roles would be good to share/transfer back?

All roles are currently being held by the backup DC now.


snusgubbenConnect With a Mentor Commented:
"repadmin /replsum" will give you a quick forest wide replication overview. Also look in the event logs and dcdiag for errors.

I'm not sure what you define as a backup DC, but you place the FSMOs where you want them to be. I'll recomend you not to split the up on different DCs.
durango099Author Commented:
Thanks snusgubben

The backup DC is defined as the secondary DC before the PDC failed. Now that the PDC is back online and the DC roles added back, I would like to transfer all FSMO roles back to it.

Mike KlineCommented:
You can transfer them, that is ok,
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.