We have a user who was experiencing freeze-ups and hangs in Outlook 2010. The system is running Win 7, Office (Outlook) 2010, against Exchange on a Win 2003 Server. Periodically, Outlook would hang with no error message. Forcing Outlook to quit (using the task manager) would work except then the system would not complete the logoff process (the system would never complete "logging off" and shutting down) and next time Outlook was started, the Outlook startup would never complete (it would hang at the splash screen).
The only way we could get Outlook to start functioning again was to go back to the install process and do a Repair.
After much trial and error, we decided to turn off the Archive capability for that specific user. (To do this, right click on Archive in the left bar and choose "close archive".) This stopped the hanging.
Turns out that Microsoft recommends that an Outlook Archive NOT be located on a network drive. OK, I can accept that (although this makes it difficult to back up archived data) but we have a good number of users who have this configuration and are not having problems. (See this article for more information -- http://support.microsoft.com/kb/297019
With a disabled Archive file, things have been running fine for 48 hours. Next step will be to add a local archive and then figure out how to get it to a place where our nightly backups will back up the file.