I have recently been doing a little server tidying for a client which involved demoting out some Domain Controllers after they had promoted in some new Server 2012 ones and I came across this strange error.[error]The operation failed because: Active Directory Domain Services could not transfer the remaining data in directory partition DC=ForestDnsZones,DC=domain,DC=local to Active Directory Domain Controller \\FQDN_of_a_DC.The directory services is missing mandatory configuration information, and is unable to determine the ownership of floating single-master operation roles.[/error]Now, I had moved all the FSMO roles to the new servers so you can imagine my confusion…….. so I did some digging. This article here gives a wonderful explanation about the Infrastructure Master role and why you receive the error above. This Microsoft Article gives a simple script to amend the issue and allow a successful demotion.