Uninstalling add-ons

From MozillaZine Knowledge Base
Jump to navigationJump to search
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
This article was written for Firefox and Thunderbird but also applies to SeaMonkey 2.0 and above. Mozilla Suite/SeaMonkey 1.x users should read Uninstalling extensions - SeaMonkey.

This article explains how to uninstall extensions and themes you no longer want. If you are troubleshooting possible problematic extensions you should first try disabling the add-on.

Note: Be careful when installing or updating other applications, which may include a toolbar or other add-on by default. A list of applications that come bundled with unwanted add-ons can be found here and here

Uninstalling extensions and themes

The usual method for uninstalling extensions and themes is by using the Add-ons manager for your Mozilla application, as follows.

  1. Click "Tools -> Add-ons" (Add-ons Manager in SeaMonkey 2)
  2. Click on "Extensions" or "Appearance" ("Themes" in Firefox 3.6).
  3. Click on the extension or theme you want to uninstall.
  4. Click "Remove" ("Uninstall" in Firefox 3.6).
  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.


If you have trouble uninstalling an extension or theme from the Add-ons manager:

  • Completely close 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 in Safe Mode then click "Continue in Safe Mode" (or "Start in Safe Mode" in Firefox 15 and above) to uninstall the extension or theme. See the Safe Mode article for details.
  • If the remove or 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.
  • If the add-on repeatedly shows "This item will be uninstalled after you restart Firefox" even after restarting, either create a new profile or try uninstalling manually (see below).

Corrupt extension files

It's possible that the files that store information about your installed extensions are corrupt, preventing you from viewing, updating, or uninstalling extensions. To resolve this, open the Profile folder (which you can do from the button in the Application Basics section of the "Help -> Troubleshooting Information" page) and then close your Mozilla application and delete (or rename) these files:

  • extensions.cache
  • extensions.ini
  • extensions.rdf
  • extensions.sqlite
  • extensions.sqlite-journal
  • extensions.json

Note: The specific extensions.* files that the profile folder includes will depend on your Mozilla application and version. Deleted or renamed files will be regenerated upon application restart, as needed. You may also have to delete the "compatibility.ini" file to rebuild some other files in the profile folder. [1] [2]

Uninstalling manually

If you are unable to uninstall an extension, even after restarting your Mozilla application in 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 extension you want to uninstall. (To uninstall ALL extensions, 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 extension the directory contains. Alternatively, in the parent folder, "extensions.rdf" contains a list of extensions, their names and corresponding GUIDs.

Note: Starting in Gecko 2.0 (Firefox 4 / Thunderbird 3.3 / SeaMonkey 2.1), XPI files are no longer unpacked when extensions are installed. Instead, the XPI itself is placed in the extensions directory, and files are loaded directly out of the package. See Updating extensions for Firefox 4 for details. [3]

Global extension

In some cases, an extension may be installed globally into the installation directory (or into the <installation directory>\browser\extensions folder, in Firefox 21 and above [4]), which enables its use in all profiles for a Mozilla application. Installing a global extension into the installation directory 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 global extension to Firefox, for the Java Console [5]).

Extensions may also be globally installed into a predefined user directory for Mozilla extensions. For example, an extension may be installed for Firefox on Windows, into the %APPDATA%\Mozilla\Extensions\{ec8030f7-c20a-464f-9b0e-13a3a9e97384}\ folder, which makes it accessible to all Firefox profiles for that Windows user. On Mac OS, a Firefox extension may be installed into the Macintosh HD/~/Library/Application Support/Mozilla/Extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384} folder for a specific user (note that the ~/Library/ folder may be hidden) or into the Macintosh HD/Library/Application Support/Mozilla/Extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384} folder, which will make it available to any user on the machine. See this MDN article for more examples and additional information. [6]

To manually uninstall a global extension, open the "extensions" or "\browser\extensions" folder in your Mozilla application's installation directory or in the user directory for Mozilla extensions and remove the directory that corresponds to the extension you want to uninstall. [7].

Note: On Windows systems, another software installation may also add an extension which is located outside of the Mozilla installation directory or other predefined user directory, via the Windows Registry. See the Windows Registry extension section below for more information.

Uninstalling an extension using Windows Control Panel

Another installed program may have added an extension to your Mozilla application. If you are unable to remove the extension using the Add-ons manager (see above) and you can't remove it from within the program's own settings, you may be able to remove it via the Windows Control Panel.

Control Panel list of installed programs

See if a separate entry for the add-on appears in the Windows Control Panel list of installed programs:

  • Windows XP/2000: "Start -> Control Panel -> Add or Remove Programs -> Change or Remove Programs" [8]
  • Windows 7/Vista: "Start -> Control Panel -> Programs / Uninstall a program (or Programs and Features)" [9] [10]

If a separate entry for the add-on doesn't exist, see if the program's entry includes the option to selectively remove individual components.

For example, CA (Computer Associates) Internet Security Suite 2008 includes the Website Inspector component, which adds the CA Link Advisor and CA Toolbar extensions in Firefox. [11] You can remove the CA Link Advisor and CA Toolbar extensions by removing the Website Inspector component from CA Internet Security, as shown here.

If entries for the removed add-ons remain in the Extensions list, exit your Mozilla application, open the profile folder and delete the files "extensions.cache", "extensions.ini", and "extensions.rdf".

Java Control Panel

On Windows, Java 6 Update 10 and above includes the Java Quick Starter (enabled by default in Windows 2000/XP) and installs the Java Quick Starter extension in Firefox. The uninstall button is not functional in the Firefox Add-on manager Extensions window because the extension is installed for all users via the Windows Registry (see below). To remove the Java Quick Starter extension you must first enable it in Firefox, if disabled ("Tools -> Add-ons -> Extensions -> Java Quick Starter -> Enable -> Restart Firefox") and then exit Firefox, open the Windows Control Panel, and double click Java. In the Java Control Panel, click the Advanced tab, click the + in front of Miscellaneous, clear the Java Quick Starter box and click OK. [12] [13]

Windows Registry extension

Installing or updating certain software on Windows can register an extension for Firefox or Thunderbird. For example, a Windows Registry entry to install a Firefox extension can be added under one of these keys:

HKEY_LOCAL_MACHINE\Software\Wow6432Node\Mozilla\Firefox\Extensions (Only on 64-bit versions of Windows)

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 extension (see Adding Extensions using the Windows Registry - MDC for details). When Firefox or Thunderbird next starts, it will notice the entry and install the extension.

Extensions that are installed this way include the Java Quick Starter extension for Firefox (see above), the Microsoft .NET Framework Assistant [14] [15] the RealPlayer Browser Record Plugin extension, [16] and the Lenovo ThinkVantage Password Manager extension for Firefox [17] [18]. Although you can disable the extension in the Add-ons manager, the Uninstall option may not be functional (it will be "greyed out). In such cases, experienced users can uninstall the extension by removing the associated Registry entry and/or the contents of the folder containing the extension; otherwise, simply disable it.

Note: The program that installed the extension may include an option or preference setting to remove it. For example, the RealPlayer Browser Record Plugin extension can be removed from Firefox by opening RealPlayer, going to "Tools -> Preferences -> Download & Recording" and unchecking the option, "Enable Web Download & Recording".

Malicious extensions

There have been a few reports of malware being installed as a hidden Firefox extension, via the Windows Registry. In the reported cases, the HKEY_LOCAL_MACHINE\Software\Mozilla\Firefox\Extensions\ key was used to install the malicious extension. This may be the case if you see a message when starting Firefox that a new add-on has been installed but nothing new is listed in the Add-ons manager and this registry key is present. See this forum topic for more information.

Uninstalling plugins

Starting in Firefox 3 and SeaMonkey 2, detected plugins are listed in the Add-ons window, accessible via "Tools -> Add-ons (or Add-on Manager) -> Plugins". [19] [20] You can disable a plugin but you cannot uninstall plugins using the Add-on Manager. In many cases, browser plugins are included as part of a larger application, so you would normally just disable the plugin instead of uninstalling the entire application. For more information, see Issues related to plugins and PluginDoc.

See also

External links

Related bug reports