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How to Uninstall an Outlook Add-On

By , About.com Guide

"The add-in cannot be loaded and has been disabled by Outlook"

Outlook is firm about its disabling that add-in of which, it seems, you should rid yourself. You've tried, of course, uninstalling the application behind the Outlook extension — but to no avail.

Outlook isn't much help in letting you know where to uninstall the disabled add-on either, or any add-in for that matter. Fortunately, it is but a short tour with a somewhat unexpected twist that takes you to the place where add-ons reside in Outlook. Trust it.

Uninstall an Outlook Add-On

To completely remove a plug-in from Outlook:

  • Select Tools | Trust Center... from the menu in Outlook.
  • Go to the Add-ins category.
  • Select either COM Add-ins or Exchange Client Extensions, depending on the type of add-in you want to remove under Manage.
    • You can see each extension's type in the Type column.
  • Click Go....
  • If the add-on you want to remove is a COM add-in:
    • Highlight the extension you want to delete.
    • Click Remove.
  • If the add-on you want to delete is an Exchange client extension:
    • Make sure the add-in you want to remove is not checked in the list.
  • Click OK.

Outlook Still Thinks The Broken Add-On is Somewhere?

If Outlook complains about an extension you can find in none of the add-in manager's lists, you can try deleting Outlook's add-in cache:

  • Make sure Outlook is not running.
  • Press Windows-R.
  • Type "%localappdata%\Microsoft\Outlook" (not including the quotation marks).
    • Using Windows 2000 or XP, use "%appdata%\Microsoft\Outlook" instead.
  • Click OK.
  • Highlight the "extend.dat" file.
  • Press Del.

Should you run into more problems starting Outlook now than you had before, restore "extend.dat" from the trash. You can select Edit | Undo Delete right in the Explorer window in which you trashed the file.

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