Howto Check for third-party Add-ins and ECEs loaded with Outlook

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To check if third party Add-ins or Exchange Client Extensions are registered to run in Outlook:

 

      Click Start | Run | Type on the Open line (without the quotes) “Regedit” and click OK

 

Add-ins registered here are user specific and will show in Outlook’s add-in menu:

 

HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Add-Ins

 

Add-ins registered here are registered machine wide and will not show in Outlook’s add-in menu:

 

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\Outlook\Add-Ins

 

Exchange Client Extension (ECE) registration:

 

HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\Client\Extension Extensions

 

If a third party add-in or ECE is suspected of causing an issue:

 

For 3rd party COM Add-ins found under HKEY_CURRENT_USER

 

· Export HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\AddIns off to an .reg file to back it up. When testing is finished, the registration entries can be restored by double-clicking on the .reg file.

 

· Delete each of the add-ins one at a time, restarting Outlook in between until the issue goes away or there are no more add-ins. If the problem goes away, then you know there is likely an issue with the last add-in removed – at that time, test with just the suspect add-in to verify. When there is an issue with a third-party add-in, the third-party company should be engaged by the customer.

 

 

For 3rd party COM Add-ins found under HKEY_LOCAL_MACHINE

 

· Export HKEY_LOCAL_MACHINE\Software\Microsoft\Office\Outlook\AddIns off to an .reg file to back it up. When testing is finished, the registration entries can be restored by double-clicking on the .reg file.

 

· Delete each of the add-ins one at a time, restarting Outlook in between until the issue goes away or there are no more add-ins. If the problem goes away, then you know there is likely an issue with the last add-in removed – at that time, test with just the suspect add-in to verify. When there is an issue with a third-party add-in, the third-party company should be engaged by the customer.

 

 

For 3rd party Exchange Client Extensions

 

· Export HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\Client\Extensions to an .reg file to back it up. When testing is finished, the registration entries can be restored by double-clicking on the .reg file.

 

· From the Extensions key: In the right-hand pane, remove one entry.

 

· Search for Extend.dat and if you find it, rename\delete the file. Chances are the file will not have regenerated itself yet.

 

· Shutdown\restart Outlook and try to repro the issue.

 

· Keep deleting one entry at a time until the issue doesn’t reproduce.

 

· Import the backed up reg key by double-clicking it.

 

· Go back and delete the last Extension entry you had removed.

 

· Shutdown\restart Outlook and try to repro the issue.

 

Checking to make sure that third-party DLLs are not loaded:

Here are some tools you can use to check what is loaded.

 

Process Explorer:

With Outlook running, you can view the loaded modules if you view the lower Pane and see what is loaded.

 

To view DLLs:

 

                View -> Lower Pane View -> DLLs

 

Windbg:

Attach to Outlook, set your symbols path and load symbols. Use “lm” to list modules. You can use “lmvm” on the module name to get information on the module (such as the company who wrote it). Also, searching on the internet for the module may provide more information.