I support a lot of clients who use Outlook 2011. My first suggestion would be to clear the cache for your calendar in Outlook. It's easy. You do this by right-clicking your calendar(s) and selecting "Folder Properties". When the Properties window opens, click the Empty button under the Empty Cache section. This will clear your local copy of the calendar, and make Outlook download a fresh copy of all of your events from the server. I see this a lot. It's a synching issue in Outlook 2011. You can do this with all of the folders in Outlook (mail folders, contacts, etc). It's advisable that all users of Outlook 2011 do this frequently with large folders if they're on Exchange, Kerio Connect, or IMAP accounts. Outlook 2011 has some nice features, but I prefer Mail, iCal, and Address Book over Outlook 2011. They don't get corrupted, and they don't crash a lot if a user has a lot of email content. I hope this helps. I didn't want to redirect you some place else. The Microsoft forums have been a lot of help for me, but as an Apple Consultant, I've had to learn a lot about Outlook 2011 since it first shipped in Oct. 2010. It's really just a remodelled Entourage. It's still prone to the same old database problems that Entourage had, which is why I won't use it.