I was installing a new domain install of SBS 2008…not a migration. However, after the install process finished, the domain admin account that was added did not have the correct permissions, Exchange 2007 wasn’t installed, and the Active Directory schema was not extended correctly. After multiple installs, I finally realized that a stand-alone server on the network had the same workgroup name as the domain name that I wanted to use. And, while I clearly installed it with the intention that this was the first domain controller, the install process seemed to view the workgroup “controller” to be a domain controller, and since the domain admin account had a different password, it couldn’t authenticate to the “domain”. Silly, and especially silly that it couldn’t come up with a simple little “Hey, dummy! Change the workgroup that one standalone computer belongs to!”, or even “Hey, there appears to be another domain here with the same name!”
Sigh.