DCPromo fails with: "The directory service is missing mandatory configuration information, and is unable to determine the ownership of floating single-master operation roles"

I was recently decommissioning an old DC as part of an infrastructure upgrade project for a client of ours. When attempting the DCPROMO process to remove the old DC, I encountered the following error:

This is very easy to resolve, however it usually is a result of an old DC that's no longer in the network that's not been decommissioned properly.

There are two types of error messages that look almost the same, however they will both hold you up when trying to decommission the server:

• ForestDnsZones
• DomainDnsZones

The same process can be followed to resolve each of these messages, and I would suggest that if you encounter the error above, then you sort these both out.

To investigate the issue, you can run the following command, which will tell you the dSMORoleOwner:

dsquery * CN=Infrastructure,DC=ForestDnsZones,DC=domain,DC=local -attr fSMORoleOwner

I received the following results, which shows the orphaned object.  You can see this by the "0ADEL:XXXXX" part in the return query.

In order to resolve this, you need to set the new server as the role owner.  This can be done in ADSI Edit.

Open up ADSI Edit and navigate to the following path:

CN=Infrastructure,DC=ForestDnsZones,DC=domain,DC=com

Right-click > Properties on 'infrastructure', and under Attribute Editor, search for fSMORoleOwner.

Now replace this with the location of your PDC which should have all the FSMO roles assigned to it:

CN=NTDS Settings,CN=ServerName,CN=Servers,CN=Perth,CN=Sites,CN=Configuration,DC=Domain,DC=com

That's it!  You're done.  If you do notice you get the following error, it will be because you're probably making this change on the troublesome DC.  Make sure you do this on one of the other working DCs and you will avoid any errors.