Duplicate junk e-mail messages appear in the Junk E-mail folder in Outlook 2003

SYMPTOMS
You receive duplicate e-mail messages in your Junk E-mail folder in Microsoft Office Outlook 2003 when all the following conditions are true:
• You have more than one instance of Outlook 2003 running on different computers, and all the instances are configured with the same Microsoft Exchange Server e-mail account.
• The junk e-mail protection level for your e-mail account is set to Safe Lists Only in Outlook 2003.
• Your Exchange Server does not filter incoming e-mail messages.
• All instances of Outlook 2003 use an Exchange Server e-mail account in Cached Exchange Mode.
• The sender of the e-mail message is not in your Safe Senders list in Outlook 2003.
• The sender of the e-mail message is not in your Contacts in Outlook 2003.
• The sender of the e-mail message is not in your Blocked Senders list in Outlook 2003.
• None of the recipients of the e-mail message are in your Trusted Recipients list in Outlook 2003

CAUSE
This problem occurs because Outlook 2003 has the junk e-mail protection level set to Safe Lists Only.

When you create a junk e-mail rule in Outlook 2003 with the junk e-mail protection level set to Safe Lists Only, the restriction structure (SRestriction) causes an Exchange Server that is running without junk e-mail filtering to decide if an e-mail message is junk e-mail or if it is not junk e-mail. Outlook 2003 then processes all the junk e-mail messages on the client side. If there is more than one instance of Outlook 2003 running, multiple copies of the same junk e-mail message can be moved from the Inbox to the Junk Mail folder while duplicates of the junk e-mail messages are created in the Junk E-mail folder.

RESOLUTION
This problem was first fixed in a hotfix that is now contained in a service pack. If you installed the latest Microsoft Office 2003 service pack, you do not have to install the hotfix.

Service pack information
This problem is corrected in Microsoft Office 2003 Service Pack 1.

To resolve this problem, obtain the latest service pack for Microsoft Office 2003. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

830003 Outlook 2003 Hotfix Package