How to Block Browser Extensions

Some browser extensions might interfere with your ability to enforce a content filter. Learning how to block these extension is an important step.

Tech Lockdown Team

Updated July 31, 2024

If you’re trying to prevent yourself from bypassing a content filter on your browser, then you might have tried researching how to block an extension. Fortunately, it is possible to block specific extensions that you definitely don’t want installed, plus block the extension store on your browser.

It is possible to block a browser extension in such a way that the option to install it is completely disabled:

However, the process for blocking a browser extension this way is not easy to find online. Typically, most articles or guides that you might find want you to use the Group Policy editor (for Windows) or full device management (for Mac). But fortunately, there is a much easier way to do this.

To fully block an extension, you won't be able to just go into your browser's settings to make these kinds of restrictions. You will have to instead use additional (or hidden) settings that can change the way a web browser functions outside of the settings tab.

What Are the Hidden Settings for Web Browsers?

You are probably familiar with the Settings page on Chrome:

Your browser also has hidden settings (called Policies) that you can’t change from this menu. One of these policies is called the ‘ExtensionInstallBlocklist’.

How exactly you go about enabling this will depend on which device you have. On Windows computers, you can edit it using the Registry. Mac devices have a similar option called the defaults system and plist files.

Fortunately, it's pretty simple to use Command Prompt or Terminal Commands to make these changes quickly.

Find the Extension's ID

First, you will have to use the extension ID in order to instruct your browser to keep it installed.

Fortunately, this is pretty easy.

Once you have an extension you want to block, go to its store page (we'll use Cold Turkey as an example):

Take a look at its URL. At the very end of the long address, you should see a forward-slash followed by a long string of letters. This string of letters is the extension ID.

Copy this ID, you will need it later. Alternatively, if you have multiple extensions that you want to install, I would create a list in Notepad so you don't forget.

Important

Different browsers have their own webstore, which means that they also have their own version of an extension. If you try to block a Google Chrome extension in Edge, it won't work unless you block the Microsoft Edge version of the extension.

Use the Registry to Block Extensions on Windows

On Windows, it's pretty easy to use either the Registry Editor or Command Prompt to add an extension to your browser's blocklist.

We'll start by using the Command Prompt to do this quickly. For some of us, it will make sense to see what's going on, so I've also provided instructions for the Registry Editor.

Keep in mind that modifying the Registry without knowing what you're doing can be dangerous. I would strongly recommend that you make a backup before continuing.

Add Extensions to Blocklist using Command Prompt

You should have the extension ID(s) of the browser extensions you want to block first.

Open Command Prompt as an Administrator.

In order to create a blocklist, you'll first need to create a directory in the Registry first called the ExtensionInstallBlocklist.

To create the directory, copy/paste this command into Command Prompt (make sure that you are running as an Administrator):

For Google Chrome, use this command:

reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallBlocklist"

For Microsoft Edge, use this command:

reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge\ExtensionInstallBlocklist"

After you've created this directory in the Registry, you can start adding entries to start building your Forcelist.

To add an entry, you'll need to use a command to add a String Value within the ExtensionInstallForcelist; before you try to run this command in Command Prompt, take a look at it:

For Google Chrome, look at this command:

reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallBlocklist" /v "1" /t REG_SZ /d "pganeibhckoanndahmnfggfoeofncnii"

For Microsoft Edge, look at this command:

reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge\ExtensionInstallBlocklist" /v "1" /t REG_SZ /d "pganeibhckoanndahmnfggfoeofncnii"

You'll see that the command starts going to the ExtensionInstallBlocklist directory first. Next, it creates a new String value with the title "1", then you might recognize the extension ID near the end for Cold Turkey: "pganeibhckoanndahmnfggfoeofncnii".

If you want to change which extension is blocked, just take the extension ID you've copied earlier and replace Cold Turkey's value with your own.

If you want to add additional extensions to your blocklist, you can, but just make sure that you change the name to "2" for the second entry, "3" for the third entry, and so on.

For example, if you also wanted to add Google translate:

reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallBlocklist" /v "2" /t REG_SZ /d "aapbdbdomjkkjkaonfhkkikfgjllcleb"

(and for Edge)

reg add "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge\ExtensionInstallBlocklist" /v "2" /t REG_SZ /d "aapbdbdomjkkjkaonfhkkikfgjllcleb"

Notice the "2" and the changed extension ID in the above command.

Add Extension to Blocklist using the Registry Editor

We'll take the same steps as you would with the Command Prompt, it just might make it easier to "see" what you're doing.

First, search for Registry in the Start Menu, and accept the User Account Control prompt:

You should see a screen that looks like this:

From here, navigate to HKEY_LOCAL_MACHINE > Policies:

If you've never done this before, you will probably have to create a Google entry. To do this, right-click on Policies and choose New > Key.

Name this new key Google:

Under Google, create another key named Chrome. Under Chrome, add one called ExtensionInstallBlocklist:

The final path should be Computer \ HKEY_LOCAL_MACHINE \ SOFTWARE \ Policies \ Google \ Chrome \ ExtensionInstallBlocklist. You can check this towards the top of the Registry Editor:

On the ExtensionInstallBlocklist entry you just created, then right-click and choose New > String Value:

Name this new String Value "1":

Double-click on this value and enter your first extension ID under Value data:

Click OK when you're done.

Perfect! The final product should look like this:

If you want to add more extensions to this blocklist, right-click on ExtensionInstallForcelist again, choose New > String Value, then set this new value's name to "2". If you had three extensions that you wanted to the blocklist, it might look like this:

Block the Extensions Web Store

If you want to prevent yourself from installing new extensions, then it might be a good idea to block the extensions web store.

Using an application blocker, you can instead get a blocked page like this:

Or this, if you opt to use Freedom Blocker:

Learn more about how to block the extensions store here.

Browsers

How to Block the Extensions Store on a Web Browser

Blocking the Extensions store is a great way to prevent unwanted extensions from being installed.

Block Extensions on a Managed Mac

You can enable managed mode on your mac to unlock highly detailed restrictions that can't be easily disabled. These restrictions go a step further than an AppLocker or Screen Time, they are enforced from a completely separate device.

Using a Mobile Device Manager (MDM), you can block a specific extension by following these steps:

Make sure you have the extension ID(s) handy:

Back in the Managed Browser config, navigate to Google Chrome and select the Extensions tab. Then, paste the extension ID in the Extension ID Blocklist table.

Once you distribute the config file to your Mac device using Manage Engine, you'll see that the extension is blocked.

If you would like to block all extensions except for one's that you've specifically allowed, follow these steps for your manage mac device:

In the config, navigate to Google Chrome > Extensions and update the allow list to include the approved extension IDs.

Note

The allowlist does not automatically install and enforce the extensions, but the user will be able to download approved extensions themselves. Add the IDs to the silent installation table if you want to enforce the use of those extensions.

Go to the blocklist section and add an entry with a *, which blocks all extensions other than the ones in your allow list

Once you distribute the config changes using Manage Engine and restart your Chrome Browser, you'll see that all non-approved extensions are blocked:

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Frequently Asked Questions

What is an Extension ID?

The extension ID is how your browser knows which extension to install. To find a browser extension's ID, go to its store page and look for the string of letters:

Does blocking an extension uninstall it?

Yes. If you add an extension to your blocklist, it should be uninstalled next time you restart your browser.

How do I remove an extension I’ve enforced?

If you need to remove an entry, the easiest way is to delete the ExtensionInstallForcelist entry in either the Registry (for Windows) or the Plist file (for Mac).

For Windows, open Command Prompt as administrator and enter the following command for Chrome:

reg delete "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallBlocklist" /v 1 /f

Here's the command for Edge:

reg delete "HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge\ExtensionInstallBlocklist" /v 1 /f

For Mac, open Terminal and enter the following command for Chrome:

defaults delete com.google.Chrome ExtensionInstallBlocklist

For Edge, use this command:

defaults delete com.microsoft.Edge ExtensionInstallBlocklist

Restart your browsers in order for the changes to take effect.