I am working through a lab scenario in preparation for an upgrade. I set up two exchange 2003 servers and then added a Exchange 2010 server with all three roles. Everything worked fine, mail flowed between the two organizations, etc. I then installed a new exchange 2010 with CAS/HUB only and removed CAS/HUB on the original server. Now users on Exchange 2010 can't connect with outlook. They get the "you must connect to microsoft exchange with the current profile before you can synchronize" error. It seems to have some problems connecting using autodiscover and if I do it manually and put in the new CAS/HUB in, it seems to at least resolve the username (where with autodiscover it doesn't even do that) but it won't connect to the mailbox. OWA works fine. A little stumped.