After months of struggling with Outlook hanging up inexplicably I found something that looks really promising. I had thought it was because I’m connecting to several Exchange servers. It was particularly bad if I switched between the Mail and Calendar windows after Outlook had been running for awhile. My solution was to open up my Calendar in a second window as soon as I opened Outlook, but that was really tedious to have to remember to switch windows instead of using the shortcuts at the bottom left of the Outlook window.
Check this out; File | Options | Advanced – Disable hardware graphics acceleration.