Our software vendor rep is trying to upgrade MS SQL server 2008 SP4 to 2012 SP1. Get an error message: no mapping between account names and security ADs was done. He says that we get this error message because we have two domain controllers in our network, and one is running on the same windows server that run sql server. Out IT support disagrees to delete the second domain controller, saying it is recommended by Microsoft and he suggests that the problem is in Active directory. Who is right? What could be a resolution for our problem?