I have Exchange 2010-2003 coexistence with one forest with one root and 3 child domains. Everything is working as should with root domain. When moving mailboxes from child domains I have insufficient rights on two, and unable to contact domain for the third. When running setup /PrepareDomains I keep getting Exchange Server setup operation didn't complete and needs reboot. I have rebooted several times and no change. All servers are 2003 SP2 and properly set for exchange 2010 install. The new Exchange 2010 server is running off 2008 R2. Exchange 2003 is running of 2003 SP2.