I can repro that bug, originally on OS2007 with a claws-mail of fairly recent vintage. This prompted me to upgrade to OS2008 and claws-mail 3.3.0, and I still have the problem.

With synchronization enabled on my inbox, claws-mail establishes the SSL connection to the IMAP server, begins to synchronize, and crashes. 100% reproducible.

With synchronization disabled, claws-mail connects to the IMAP server and displays my inbox. I can read messages, etc.

Looking at the comments on bug 1341, it seems likely that one particular message is causing the crash. Is there a way to get debug output so I can maybe figure out which message is to blame?

logicprobe