Welcome to Outlook Programming series # 9
In this series, we will learn "How to systematically release the objects - Add-in's for Outlook 2003 & Outlook 2007 ?". I found this MSDN article which describes how all Outlook add-ins should systematically release their references to Outlook objects when they are no longer needed. Failing to systematically release reference to Outlook objects can prevent Microsoft Office Outlook 2003 & Outlook 2007 from shutting down properly.
For more information about this problem that affects managed add-ins written for Outlook 2003 using Visual Studio .NET, see KB 317109: Office application does not quit after automation from Visual Studio .NET client.
Please find Mstehle's blog: OOM.NET: Part 2 - Outlook Item Leaks (Outlook + OOM + .Net Issues), which describes in detail and has the resolution to solve the issue...