I’ve been running Evolution 2.8.1 on Ubuntu 6.10 for a few months without any problems. Today Evolution started reporting that it has lost it’s connection to Exchange:

"Can't get message, Lost connection to Evolution Exchange backend process"

After half a day of the Exchange web mail interface driving me crazy I finally fixed the problem. The solution turned out to be simple. After removing the Exchange account from Evolution and quitting it I ran the following commands to remove all evidence of Exchange:

% evolution --force-shutdown
% cd ~/.evolution
% rm -rf `find . -name *exch* -print`

I then restarted Evolution and added the Exchange account again.

Warning: Before removing any files or directories you should back up your entire ~/.evolution directory just in case something goes wrong and you need to restore it.