Fix: Firefox Addons not Working

The Firefox add-ons might not work if your Firefox browser is not up to date. Moreover, incorrect date/time settings of your system or corrupt Firefox user profile (or any of its settings/files) may also cause the issue.

The user encounters the issue when he launches Firefox and the browser launches but either without addons (icons do not show) or the addons do not work at all (for some of the users, the issue was limited to some addons). The issue is reported on nearly all the major operating systems, usually after a Firefox update.

Firefox Addons Not Working

Before moving on with the solutions to fix the Firefox addons, restart your system to rule out any temporary glitch. Moreover, make sure the addons are activated in the addons menu of the Firefox browser. Last but not least, do not forget to update your Firefox browser to the latest build.

Solution 1: Re-enable the Firefox Add-ons

The addons issue could be a result of a temporary glitch in Firefox. The glitch can be cleared by disabling and enabling the Firefox addons and thus solve the problem. This action re-initializes all the add-on modules and starts them afresh.

  1. Launch the Firefox browser and open its menu by clicking on the hamburger menu near the top right of the window.
  2. Now, in the menu shown, click on Addons and then disable every addon by toggling its respective switch to the off position.
    Open Add-ons in the Firefox Menu
  3. Then enable the addons and check if the addons issue is resolved.
    Disable/Enable Firefox Extensions
  4. If not, then install another addon to check if Firefox is working fine. You can also download the Firefox addon through another browser (preferably Chrome) and then drag-drop the addon to Firefox to check if the addon issue is resolved.
  5. If not, then try to launch Firefox in Safe Mode and remove any of the problematic extensions (you can also remove all the extensions) there to check if they were causing the issue.
    Click Start in Safe Mode to Confirm Firefox Safe Mode

Solution 2: Correct Date and Time of Your System

The date and time of your system are used for many operations (like syncing of different services) by different applications. You may encounter the error at hand if the date and time of your system are not correct which in turn conflicts with Firefox’s own internal date-time engine. In this scenario, correcting the date and time of your system may solve the problem.

  1. Right-click on the clock (shown in your system tray) and in the resulting menu, click on Adjust Date/Time.
    Adjusting date/time
  2. Now, disable the options of Set Time Automatically and Set Time Zone Automatically.
  3. Then click on the Change button (under the option of Set the Date and Time Manually) and then adjust the date and time.
  4. Now set the correct Time Zone of your system and then check if Firefox is clear of the error.
    Manually Adjust Date Time of Your System
  5. If not, then try to set the date of your system to one day back and check if the issue is resolved.
  6. If even moving one day back doesn’t work, then try to set the date to the correct one and check if the Addons issue is resolved.

Solution 3: Disable extensions.webextensions.remote Firefox Preference

The extensions.webextensions.remote Firefox preference (when enabled) is used for disabling all the out of process extensions. You may encounter the error at hand if, due to a glitch, Firefox “thinks” all the extensions as out of the process. In this case, disabling the said preference may solve the problem.

  1. Launch the Firefox browser and key-in the following in the address bar:
    about:config
  2. Now click on the button to Accept the Risk and Continue.
    Accept the Risk and Continue to Open about:config Menu of Firefox
  3. Then search for the following preference in the Search Preference Name box:
    extensions.webextensions.remote
  4. Now, click on the toggle switch to change its value to False (if True) and then relaunch the Firefox browser.
    Disable extensions.webextensions.remote
  5. Upon relaunch, check if the Firefox addons are operating normally.

Solution 4: Remove the Toolbars and Buttons Customization

Users tend to customize toolbars and buttons as per their requirements but this customization may lead to the current addons error. In this case, restoring toolbars and buttons to the defaults may solve the problem.

  1. Launch the Firefox browser and click on the hamburger menu (near the top right of the window).
    Open Customize in the Firefox Menu
  2. Now, in the menu shown, click on Customize and then, in the resulting window, click on Restore Defaults (near the right bottom of the window).
    Restore Toolbars and Buttons in Firefox to Defaults
  3. Then check if the Firefox addons are working fine.

Solution 5: Disable Dom Storage of Firefox

DOM Storage provides a way to use a more secure, larger, easier-to-use alternative for storing the information in the browser cookies. The Firefox add-ons might not work if the Dom Storage of Firefox is in an error state which in turn blocks the operation of add-ons. In this case, disabling the Dom Manager may solve the problem.

  1. Launch Firefox and in its address bar, type:
    about:config
  2. Then confirm to Accept the Risk and Continue.
  3. Now, type the following in the Search Preferences Name box:
    dom.quotaManager.useDOSDevicePathSyntax
  4. Then click on the toggle switch to change its value to False (if already True).
    Disable dom.quotaManager.useDOSDevicePathSyntax
  5. Now relaunch Firefox and check if it is clear of the addons error.

Solution 6: Enable History in the Firefox Options

Firefox has a bug in which it may disable addons if remembering history is disabled. In this scenario, enabling the remember history option may solve the problem.

  1. Launch the Firefox browser and open its menu (by clicking on the hamburger menu near the top right of the window).
    Open Firefox Options
  2. Now, in the resulting menu, select Options and then, in the left half of the window, select Privacy & Security.
  3. Then scroll down and in the History section, expand the dropdown of “Firefox Will”.
  4. Now, in the dropdown, select Remember History and then check if the issue is resolved.
    Enable Remember History in Firefox

Solution 7: Edit Extensions.json File to Allow Addons Operation

Firefox add-ons may not work if entries in the Extensions.json file are not properly configured (that may stop addons from working). In this case, editing the Extensions.json file to let the addons operate may solve the problem.

  1. Launch Firefox and in its address bar, type:
    about:support
  2. Now, in the Applications Basics table, click on the Open Folder button (in front of Profile Folder) which will open the Profile folder in the File Explorer of your system.
    Open Profile Folder of Firefox
  3. Now, minimize the Profile folder and exit Firefox. Also, make sure none of the Firefox related processes are running in the Task Manager of your system.
  4. Then, switch to the Profile folder and open the extension.json file with your preferred text editor (e.g. Notepad, etc.).
    Edit Extensions.json in Firefox Profile Folder
  5. Now press Ctrl + F keys to open the search box and search for appDisabled. Then change all of its values to False (if True).
    Turn Off appDisabled in extensions.json
  6. Then search for signedState and change its value to 2 (if set to 1).
    Turn Off signedState in Extensions.json
  7. Now save and close the Extensions file.
  8. Then restart your system and upon restart, launch Firefox and check if its addons are clear of the error.
  9. If not, then disable/enable add-ons one by one and check if the issue is resolved.

Solution 8: Remove All Files from Storage Folder of the Firefox User Profile

You may encounter the error under discussion if the profile storage of Firefox is corrupt. This usually occurs after a bad update or when your operating system files are moved. In this case, deleting all the files from the Storage folder of the Firefox user profile may solve the problem (the files will be recreated on the next launch of Firefox).

  1. Launch Firefox and type about:support in its address bar.
  2. Then, in front of the Profile Folder (in the table of Applications Basics), click on the button of Open Folder.
  3. Now, minimize the Profile folder and close the Firefox browser (make sure not Firefox related process is running in the Task Manager of your system).
  4. Then switch to the Profile folder and then open the Storage folder.
    Open Storage Folder in the Firefox Profile Folder
  5. Now delete all of the contents of the storage folder and then restart your system.
    Delete the Contents of Storage Folder of Firefox Profile
  6. Upon restart, launch the Firefox browser and check if its addons are working fine.

Solution 9: Delete Extension Files from the Firefox User Profile

Add-ons may also fail to work if the file storing the extensions registry is corrupt. In this scenario, delete the extensions from the Firefox user profile may solve the problem (do not worry, files will be recreated on the next launch of Firefox).

  1. Launch the Firefox browser and in its address bar, type:
    about:support
  2. Now scroll down and in the table of Application Basics, click on the Open Folder button in front of Profile Folder (which will open the Profile folder window in the File Explorer).
  3. Now, minimize the Profile folder window and close the Firefox browser (make sure no Firefox related process is running in the Task Manager of your system).
  4. Then switch to the Profile folder window and delete all the extensions files there.
    Delete All the Extensions Files in the Firefox Profile Folder
  5. Now delete the compatibility.ini file and then restart your folder.
    Delete Compatibility.ini File in the Firefox Profile Folder
  6. Upon restart, launch Firefox and check if the addons issue is resolved.

Solution 10: Create a New Firefox Profile

The Firefox add-ons might not work if your user profile of Firefox is corrupt. In this context, creating a new user profile may solve the problem. Before proceeding, make sure to backup essential information/data of the Firefox browser and its extensions.

  1. Create a new Firefox user profile.
  2. Now, check if the addons issue is resolved. If so, then you can copy the cert9.db to the old profile to check if it was causing the issue.

Solution 11: Refresh Firefox

The addons issue could be a result of a conflicting addon or misconfiguration of a setting of the Firefox browser. In this context, refreshing the Firefox browser (that will remove all the addons/customizations and restore the browser settings to their defaults) may solve the problem as there isn’t any other way we check for the integrity of the application files.

  1. Launch the Firefox browser and click on the hamburger menu.
  2. Now click on Help and then click on Troubleshooting Information.
    Open Troubleshooting Information in the Help Menu of Firefox
  3. Then, in the window shown, click on the Refresh Firefox button and then confirm to refresh the Firefox browser.
    Refresh Firefox
  4. Now, after refreshing the browser, check if Firefox is operating fine.
  5. If not, refresh Firefox (as discussed above) and then enable the option of Remember History (if disabled) as discussed in solution 7 to check if the issue is resolved.

Solution 12: Change the Certificate Requirement of Addons

Firefox browser may not operate add-ons if the certificate required (add-ons require a certificate to operate so that the malicious add-ons could be curbed) for the add-ons is corrupt or expired. In this case, disabling the certificate requirement of the add-ons may solve the problem.

Warning: Proceed at your own risk as disabling the certificate requirement of addons may expose your system to malicious addons and can be a threat to your system/data.

  1. Launch the Firefox browser and type about:config in its address bar.
  2. Then Accept the Risk and Continue.
  3. Now, search for xpinstall.signatures.required in the Search Preference Name and then click on its toggle switch to change its value to False (if True).
    Disable xpinstall.signatures.required in Firefox
  4. Then relaunch Firefox and hopefully, the addons issue is resolved.

If the issue is there, then try to use debug mode of Firefox (type about:debugging in the address bar and then click on This Firefox. Now click on the Load Temporary Add-ons to use the addons temporarily).

Load Temporary Add-on Firefox

You can also try to copy the Mozilla folders from %appdata% and %localappdata% of a working installation of Firefox to the problematic system.

Kevin Arrows


Kevin is a dynamic and self-motivated information technology professional, with a Thorough knowledge of all facets pertaining to network infrastructure design, implementation and administration. Superior record of delivering simultaneous large-scale mission critical projects on time and under budget.

Expert Tip

Fix: Firefox Addons not Working

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