Situation:
After installing Norton Internet Security or Norton AntiSpam, you see an error message titled "Managed MAPI Service Catastrophic Failure" when opening Outlook 2003. You may also see the text "Unknown error" in the error message window.
Solution:
This problem was fixed by the latest Norton AntiSpam 2005 program update. To install the update, start Norton AntiSpam or Norton Internet Security, and then click LiveUpdate. Download all available updates, including the Norton AntiSpam program update, and then restart the computer if prompted. For more details on how to run LiveUpdate, see the document How to run LiveUpdate.