Add-ons that cause stability or security issues are put on a blocklist

Firefox Firefox Last updated: 09/21/2023 47% of users voted this helpful

When Mozilla becomes aware of add-ons that violate our Add-on Policies and jeopardize user safety or privacy, or that otherwise go against user expectations, we may take steps to block them from running in Firefox.

Why does Mozilla block some add-ons from running in Firefox?

While most add-ons are created with the best intent to provide useful and delightful features, they can also be used to compromise personal data and security.

When we become aware of add-ons that pose a risk to your security and privacy according to our Add-on Policies, we take steps to prevent them from running in Firefox. Add-ons may be blocked proactively because they violate our policies, or in response to an abuse report.

For more information, please read the Add-on Blocking Process article on Firefox Extension Workshop.

How does add-on blocking work?

Once a block is implemented, Firefox will disable the add-on and you will not be able to override the block. Blocked add-ons cannot access your browsing activities or deliver malware.

For more technical information about how blocking works, please read Introducing a scalable add-ons blocklist on the Add-ons Blog.

How will I know if an add-on is blocked?

If you suspect you have installed an add-on that has been blocked, you can verify its status by going to the Firefox Add-ons Manager.

Click the menu button Fx89menuButton, click Add-ons and themes and select Extensions. Any blocked extensions will appear in the “Disabled” section. They will display a label that explains the extension has been disabled due to security or stability issues.

Blocked Add-on - Add-ons Manager

I see a blocked add-on in my Add-ons Manager. What should I do?

You do not need to take any action if you see a blocked add-on in your Add-ons Manager. The add-on is disabled and cannot access your activities or deliver other malware. If you would prefer, you can now safely remove it.

Since some malicious add-ons gather and sell data collected from their users, you may want to check Firefox Monitor to see if your personal information was exposed in a breach.

Can I install an add-on after it has been blocked?

Once an add-on has been blocked, Firefox will prevent you from installing it. You will see this notification:

Notification - Add-on is blocked and cannot be installed

Can blocks be lifted?

Depending on the severity of the violation, the abuse history of the developer, and other relevant factors, some blocks may be lifted once the developer uploads a new version that is approved by Mozilla. If that happens, users who had previously downloaded the add-on will immediately be able to use it again once the add-on has been updated to the latest approved version.

To make sure you are always using the most up-to-date version of an add-on (extension or theme):

  1. Click the menu button Fx89menuButton, click Add-ons and themes and select Extensions.
  2. Click on the settings icon Add-on Tools Icon and make sure that the Update Add-ons Automatically menu item is checked.

How can I find a replacement for a blocked add-on?

You can look for a replacement on, Mozilla’s official directory of add-ons. We suggest browsing the Recommended Extensions program to find add-ons that meet our highest standards of security, functionality, and user experience.

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