This problem has been around since the old Windows Inbox program. If this COM add-in truly gets rid of Outlook, why, oh why can’t they just put it in the next SP of Outlook?
If you have problems with Outlook remaining in memory when you exit it, Outlook Shutdown Addin is for you. This is a COM add-in which enables Outlook to shutdown completely when a user exits from the application, eliminating the need to open Task Manager to end OUTLOOK.EXE.
[Slipstick - Outlook and Exchange News]