This is a quick and stupid one but I thought I’d put it online in case someone else runs into this problem.

If you’re migrating from one Exchange server to another but leaving your stand-alone BES 5 server intact, make sure you’re using the latest version of BES. Exchange 2010 wasn’t supported until something like 5.0.1 SP1 but double-check that.

Second, check your MAPI profile after the new server is in. Open the Blackberry Server Configuration application, Blackberry Server tab, and hit the button to configure the MAPI profile. Make sure you’re logged in as BESADMIN or whatever user you created to manage your BES server and services. I’m not sure whether it’s supposed to reconfigure itself the same way Outlook does but I don’t think so, making it odd that I didn’t find this instruction anywhere as I was researching.

Give me a shout if this helps you out.