I'm in the midst of migrating from Exchange 2007 to 2013 and have run into a bit of a roadblock. While trying to prep AD for Exchange 2013 running Setup.exe /prepareschema the installation fails with "Cannot find the Recipient Update Service responsible for domain" and "One or more servers in the existing organization are running Exchange 2000 or Exchange Server 2003. Installation can't proceed until all Exchange 2000 or Exchange 2003 servers are removed."
I'd like to know where to look for instances of these remnants and how to safely remove them. Any help would be appreciated.