If the Outlook 2003 users are configured for Cached Exchange mode, they're
also using the Offline Address Book. The OAB probably isn't rebuilt on your
server more than once a day. Then Outlook will have to download it, which
may not occur until Outlook is restarted. You might find the article at
http://support.microsoft.com/default.aspx?scid=kb;en-us;841273 helpful.

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Sue Mosher, Outlook MVP
Author of
Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx
> When I add an object to active directory (such as a new user), and then
> create a new exchange account for that user, the new user does not show up
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> clients?
> Thanks!