Why is Outlook 2007 sending duplicate emails?

Here's the specs of the machine, the Operating system and the main applications installed:

HP Elitebook 6930 laptop
4 GB RAM, 160 GB 5400 RPM drive
Windows XP Pro SP3
Office 2007 SBE (upgraded from Office 2003 SBE)
X1 indexing software
AVG 8.0 Enterprise


Sporadically - every couple days - recipients of this user's emails will complain that they have received duplicate emails (3).  One right on top of the other.

This happens to recipients in the organization and outside of the organization.  Using Outlook Web Access does not replicate the problem, so it must be a client-side culprit.  Also, the problem first showed up in Outlook 2003.  Upgrading to Outlook 2007 has not helped.  Please help!
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Can you post the message headers for the 2 duplicate emails from the external recipients mailbox?  This may give us a clue to what is happening.
If your check the users senders sent Items box does the email show up more than once?
Do you use Microsoft Exchange?

Things to check:
Outlook Rules:  Make sure the user does not have any rules that CC, or BCC recipient emails.

Check your Antivirus software to see if perhaps it may be breaking the email into several emails for each email address.  In this case if the recipient is listed in the email and is part of a distribution group listed in the email they may get multiple emails as the AV may not be checking and consolidating duplicate recipients.

Can you create a new Outlook profile and see if that will replicate the problem? If so, try setting up the profile on a different machine to try and replicate it there.

Control Panel > Mail > Show Profiles > Add Profile.
You'll have to tell it not not default to the original profile too.
One more thing to look at from another EE post:  http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/Q_22983885.html

"I ran into the same problem with users running Outlook 2007, 2003 and Express on XP.  The issue seems to be linked to the "server timeout" value on the sender's copy of Outlook -- and a bug in the Outlook resend function.  Anything that delays the send process can trip the limit, e.g. emails that have large file attachments, a slow wireless connection, slow email server response, and delays caused by antivirus scans.  This can occur whether the user is linked to an Exchange server, Unix email server or simply connecting to the Web to via an ISP.  

If the timout is tripped, Outlook continues to 'retry' -- even though the message was already sent.  In one case, an employee sent an email with a 4Mb file attachment -- and the recipient received 42 copies before his mailbox filled up!  (Which caused yet-more problems...)

The best solution appears to be to increase the server timeout value in Outlook -- to 5+ minutes if you have a fast connection, or more if the connection and throughput are slower.   (Select the main email account and pick edit/change, then "More Settings" then the "Advanced" tab.)"

In some Outlook versions you may need to change the Server Connection Timeout from 30 seconds to 60 seconds or more.  (Select the main email account and pick edit/change, then "More Settings" then the General Tab)

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One other item to check is the PST file. If it has been migrated through several versions of outlook, it will retain it's original size limits.
I have seen a messages get sent several times, as outlook is not able to create the email in sent items, due to size limits being reached.
Try creating a new PST file and set it as default to test.
JiveITAuthor Commented:
Thanks for the suggestions, people.  I am going to try to get the headers from the duplicate emails and post them here..
JiveITAuthor Commented:
I believe that we have solved the issue.  We reinstalled X1 and disabled the Window Search in the startup processes.

The problem has not returned!
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