From MozillaZine Knowledge Base

This article was written for Firefox and Thunderbird but also applies SeaMonkey 2 (not yet released). Mozilla Suite/SeaMonkey 1.x users should read Uninstalling extensions - SeaMonkey.

Uninstalling extensions and themes

Add-ons (extensions and themes) can be uninstalled using the Add-ons manager, as follows.

1. Click "Tools -> Add-ons"
2. Click on the Extensions or Themes button on the top.
3. Click on the extension or theme you want to uninstall.
4. Click Uninstall.
5. Restart your Mozilla application.

Uninstalling an extension might not completely remove all of the extension's data. For example, if you reinstall the extension, then you might find that it still uses its previous settings. There is no general way to remove all of an extension's data. See Resetting preferences for how to remove added preferences and restore the default preference values.

Troubleshooting

If you have trouble uninstalling an add-on:

• Make sure you completely closed your Mozilla application after clicking Uninstall by using the File menu and selecting "Exit" or "Quit". You can even restart your system to make absolutely sure.
• If something is wrong that prevents you from accessing the Add-ons manager, you can restart Firefox or Thunderbird in Safe Mode to uninstall the extension or theme. (In Firefox, click "Continue in Safe Mode" after the "Firefox Safe Mode" window appears. See the linked article for details).
• If the uninstall button and menu item are disabled, the add-on is locked. To uninstall a locked add-on, you'll first have to unlock it via Safe Mode.
• The add-on repeatedly shows "This item will be uninstalled after you restart Firefox" even after restarting. In this case, do not use the uninstaller extensions. Either create a new profile or try uninstalling manually.
• If you're using Firefox 1.5 or Thunderbird 1.5 and you have an entry in the extensions list that ends in ".xpi" and does nothing when clicking on it, Exit your Mozilla application and delete the following files from your profile folder [1] [2]:
  • extensions.cache
  • extensions.ini
  • extensions.rdf

Uninstalling an add-on manually

If you are unable to uninstall even from within Firefox or Thunderbird Safe Mode:

Exit your Mozilla application, go to your profile folder and open the "extensions" directory. Each directory there is an extension. Remove the directory that corresponds to the add-on you want to uninstall. (To uninstall ALL add-ons, remove the entire "extensions" directory)

If an add-on directory there does not have a meaningful name, look inside it for its "install.rdf" file. Open that file in a text editor (such as Notepad) to see which add-on the directory contains. Alternatively, in the parent folder, "extensions.rdf" contains a list of add-ons, their names and corresponding add-on GUIDs.

Global add-on

In a few cases, an add-on may be installed globally. Installing an add-on globally is something an administrator might do so that the add-on can be used by any user on the machine. It is also possible that another software installation may have included a global extension (for example, the Java JRE installer adds a hidden global extension to Firefox, for the Java Console [3]).

To manually uninstall a global add-on, open the "extensions" directory in your Mozilla application's installation directory and remove the directory that corresponds to the add-on you want to uninstall. [4].

Windows Registry add-on

In rare cases, a third-party software installer can register add-ons for Firefox or Thunderbird. For example, a Windows Registry entry can be added for Firefox under one of these keys:

HKEY_CURRENT_USER\Software\Mozilla\Firefox\Extensions\
HKEY_LOCAL_MACHINE\Software\Mozilla\Firefox\Extensions\

The Registry entry name will be the ID name or GUID of the add-on and the value data will be the path to the folder containing the add-on (see Adding Extensions using the Windows Registry - MDC for details). When Firefox or Thunderbird next starts, it will notice the entry and install the add-on. The Lenovo ThinkVantage Password Manager extension for Firefox can be installed this way; you will be able to disable the extension but you will not be able to uninstall it using the Add-ons manager. If you are an experienced user, you can uninstall the add-on by removing the associated Registry entry; otherwise, simply disable it. [5]

See also

• Uninstalling toolbars

External links

• Uninstalling add-ons (Firefox) at support.mozilla.com
• Cannot uninstall an add-on (Firefox) at support.mozilla.com