I've got a laptop user using outlook 2007 who connects to our 2010 exchange server over RPC. Everything seemed to work okay after he was set up, but about a week later when his outlook client tried to sync with the exchange server it gets stuck when trying to sync the offline address book. It just hangs there. I've let it run for 2 hours and it just sits. I've got other users with Outlook 2007 and 2010 (though the majority of our users are 2003 users) and none of them have reported this problem, which makes me think it isn't an issue with our exchange server but just this one user. I've tried to wipe his profile from outlook but that didn't help, I've deleted the OAB to no avail, I've tried creating a brand new profile and turning off download OAB from the sync options.