Outlook recipient added randomly and automatically

Question

One user in our exchange organization is randomly and automatically added to the TO or the CC field when a sender is sending e-mail. This sometimes happens when a new mail is started and more often, but NOT always when someone replies to an e-mail. Because it is happening often and with various users we ruled out that it has something to do with the autofill option in Outlook.
searching internet did not come up with any similar problem.
Exchange 2003, outlook 2003
At this moment we only know this occurring with only one recipient. But not sure because this kind of errors are not always reported, one can think it is a mistake one made by himself, outlook autofill.

Answer 1

Hi Pieter,
I am sorry for delay in response.
As the issue occurs randomly and cannot always be reproduced, I would like to explain that we may take a long time to troubleshoot and narrow down the issue.
I think the issue can be caused by two factors:
1. The Outlook add the specific recipient to To/CC list when submit the message to Exchange Server
2. The Exchange server add the specific recipient to To/CC list when process the message.
As when the issue occurs, the specific recipient can be located in the message in the Send Items folder of the sender. I suspect the issue may related to Outlook Client. I suggest we attempt the following steps on a problem sender client which the issue occurs mostly frequently to troubleshoot the issue:
Step 1: Disable Outlook 2003 third-party Add-ins  
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1. Launch Outlook application.
2. Click Tools --> Options, click Other tab.
3. Click Advanced Options.
4. Click COM Add-Ins button.
5. Uncheck All Add-ins.
6. Backup these registry entries and then delete them one by one.
HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\Client\Extensions
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\Outlook\Addins
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\11.0\Outlook\Addins
HKEY_CURRENT_USER\Software\Microsoft\Exchange\Client\Extensions
HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Addins
HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Addins
Note: If some of them are not existed, please ignore.
Step 2: Clear corrupted Rules by using MFCMapi tool:
====================================
You can refer to following article:
How to delete corrupted and hidden rules from a single mailbox in Outlook 2003
http://support.microsoft.com/kb/924297/en-us
Note: If it is possible, I suggest that you do not import the rules to the Outlook 2003 temporarily for test purpose. Nevertheless, if we need to import rules to Outlook 2003, please check whether any sending message rules (Apply this rule after I send the message) are configured. If the rules are configured, please delete them to check the result.
Step 3: Please start Outlook by using /Safe switch and monitor whether the issue occurs again.
Step 4: Check if 3rd party DLL files exist by using Process Explorer on the client
=================================
1) Download Process Explorer from the following site:
http://www.microsoft.com/technet/sysinternals/Utilities/ProcessExplorer.mspx
2) Launch Outlook application.
3) Run Process Explorer as administrator, accepted license.
4) Locate to outlook.exe, and select Outlook.exe, click view --> Lower Pane View --> DLLS, and then click “Company Name” to sort by company name.
5) Check if there are any third-party company’s add-ins still exist.
In addition, please enable message tracking on the exchange server (I assume that you have only one Exchange server in the environment).
In case the issue occurs again, please help me gather the related message tracking log to me at [email protected]. Please also let me know:
1. The Sender name and email address
2. The recipient name and email address
3. The problem message id
4. The “Not Intended” user name and email address
Thanks,
Mike
PS: Would you please let me know how often the issue occurs normally?