I encountered this as well, and after doing some research on Gnome's Bugzilla, found this entry which helped me:
http://bugzilla.gnome.org/show_bug.cgi?id=323452 Basically, one of my email accounts is set to an IMAP server with the security protocol set to 'Whenever Possible', and Evolution would hang upon startup. Once I changed it to 'Always', the program started up just fine. I hope that this helps someone... -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
