All Outlook clients hangs when exiting

[Neil]

Starting last week every Outlook 2000 client hangs when users try to exit.
They get the following error

Event Type: Error
Event Source: Application Hang
Event Category: (101)
Event ID: 1002
Date: 10/17/2003
Time: 8:07:01 AM
User: N/A
Computer: xxxxxxxx
Description:
Hanging application OUTLOOK.EXE, version 9.0.0.6604, hang module hungapp,
version 0.0.0.0, hang address 0x00000000.

This occur on about 12 systems with either Windows 2000-SP4 or XP-SP1.
Outlook 2000 has SP3 installed.
Same problem if I un-install and re-install Outlook 2000

Outlook appears to run normally. Only crashes when exiting

Running off Exchange 2000 SP3a

Any input?
/Neil