I have successfully installed Exchange 2013 CU1 on Server 2012 with an existing SBS2008 server that has Exchange 2007. I wanted to try moving one mailbox to the 2013 database but when I click on the Migration in the ECP an error pops up that says"The user does not have an Exchange mailbox" even though there are no migration listed.
If I add a new migration batch, I can get all the way through until the end and then I get that error again.
I decided to try and move a mailbox using Exchange Management Shell and the mailbox moved with no problems (that I can tell).
Any idea what could be causing this error in the ECP?