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Troubleshooting Problems with Microsoft Outlook Add-Ins


Third-party add-ins (such as desktop antivirus scanners) cause a disproportionately high number of connection-related issues in Outlook.

The easiest way to test this is to start Outlook in “safe” mode, which disables all add-ins.  To do this, shut Outlook down completely, by choosing “File – Exit”, and then hit Ctrl-Alt-Delete to enter the Task Manger.  From there, click the “Processes” tab, and terminate any processes called “OUTLOOK.EXE”.  Next, go to “Start – Run”, and type in “outlook.exe /safe”. (Note that there MUST be a ‘space’ character between ‘outlook.exe’ and ‘/safe’.)

If running in “Safe Mode” fixes whatever connection issue you were having, the next step is to restart Outlook normally and start disabling or removing Add-Ins.  There are two areas you’ll need to check – “COM+ Addins”, and “Exchange Client Extensions”.  These are accessed differently on Outlook 2007 and Outlook 2003.

For Outlook 2010:  Go to “File – Options – Add-ins”.  Click the “Go” button that’s located towards the bottom of the window.


Add-ins section


For Outlook 2007:  From within Outlook, navigate “Tools – Trust Center – Add-ins”.  Towards the bottom, choose “COM Add-ins” and click “Go”.


COM Add-ins at bottom of the screen


For Outlook 2003:  Within Outlook, choose “Tools – Options”, and then click the “Other” tab, and then the “Advanced Options” button.  Towards the bottom of the screen you’ll see a button labeled “COM Add-Ins”.  Click that.

You’ll get to a window with a number of Add-ins listed:


Add-ins list


Start by disabling everything except the four items highlighted in green, above (if you have them):  Microsoft Exchange Unified Messaging, Microsoft Office Sharepoint Server Colleague Import Add-in, Microsoft Outlook Mobile Service, and Microsoft VBA for Outlook Addin.  These are normally included in the base Outlook 2007 install.  Then click OK.


In Outlook 2010:  No further steps are needed.

In Outlook 2007:  From within Outlook, navigate “Tools – Trust Center – Add-ins” (same as above).  Towards the bottom, choose “Exchange Client Extensions” and click “Go”.

In Outlook 2003:  Within Outlook, choose “Tools – Options”, and then click the “Other” tab, and then the “Advanced Options” button.  Click the button labeled “Add-In Manager”.

The window that pops up will look something like this:


Add-In Manager


The four items shown in the window above are fine… anything other than these four you’ll want to uncheck, and then click OK.

Outlook should now be running in close to the same state as in Safe Mode.  If you’re not experiencing any issues, go back into the Add-in Manager and COM Add-ins areas and begin re-enabling any necessary Add-ins one-by-one, keeping an eye on whether or not your connection issues reappear.

We have listed a number of Add-Ins below that have historically caused problems.  If you have one or more of these installed, we would recommend uninstalling them and if necessary, finding replacements.



Many antivirus packages – most notoriously, Norton/Symantec and McAfee

Disable the email/Exchange/Outlook active scanning feature from within the antivirus app, or switch to either AVG Antivirus or Avast Antivirus

Google Desktop/Google Search

Uninstall these from Control Panel – Add/Remove Programs

Fax Server

Click “Remove” from the Outlook Add-In Manager

Outlook Business Contact Manager

Uninstall this from Control Panel – Add/Remove Programs