Have you tried running:

1. Detect and Repair (office diagnostics in Outlook 2007)
2. Scanpst.exe against the .pst file

--
Milly Staples [MVP - Outlook]

Post all replies to the group to keep the discussion intact.
ALWAYS post your Outlook version.
How to ask a question: http://support.microsoft.com/KB/555375


After furious head scratching, jain asked:

| I and others that i know keep getting this message on starting up
| outlook: - outlook not closed properly and so it goes into
| unnecessary checking which makes you loose sometimes an hour to
| startup (see additional details later)
| - sometimes for no reason the computer shuts down totally
| - and when you try to shutdown mostly it doesnt and you have to
| hard-shutdown it
| Maybe the outlook reason is (for the other 2 conditions i have no
| clue why) -an extn failed to initialize, cant open extend. dat. the
| file may not exist....
| - error in registry for extension - exchange extensions. the syntax or
| format of registry is incorrect..
| pls reply to