Bug 78421

Which version of Evolution are you running?  How you are connecting to your mail
server (local, pop, imap)?  Do you access the same server with another email
client (at another location)?

I have had Evolution up on my workstation for over a week now without a problem.

I am using evolution 1.0.8-10.
The protocol I'm using is IMAP.
Sometimes I ssh from home to our mail server and check my mail with pine.

That's the big kicker.  I have noticed that Evolution does not handle IMAP
connections very well if another client attempts to obtain the mail box lock. 
You see, once Pine opens up your mailbox file it says something to the effect
that "another client has mailbox - attempting to retrieve lock".  The imap
server itself was the "client" that possessed the original lock.  Once Pine has
achieved a lock on the file, Evolution should treat your mail folders as read
only until it can successfully retrieve the lock again (after about 2 minutes of
the lock being freed up).  Mozilla Mail and Outlook Express are more graceful in
handling another client "steal" the lock.

Workaround : ensure that you shutdown Evolution (or switch to OFFLINE mode)
prior to accessing your mail box from a different location.  OR switch to a
different email client.

Nothing about this is going to be fixed at the Red Hat level -- I will note,
though, that 1.2 is a lot better about handling these states more gracefully.