It happens all the time since every application uses MAPI to get some information from your MAPI profile. My advice is to close Microsoft Office Groove, Office Communicator, Messenger(s), the sidebar on Vista (I have 2 Outlook gadgets running there), every other application suspicous of using MAPI (getting any kinds of information from your inbox), every other Office applications, *THEN* close Outlook. It will exit smoothly. I guess, it's because the other applications are using a shared MAPI session that Outlook opened first and OUTLOOK.EXE holds that session.