[Tip] Disable “Default Browser Agent” After Installing Mozilla Firefox

Many readers asked me to write a detailed article about the new “Default Browser Agent” feature introduced in Mozilla Firefox web browser, so here we go.

If you installed a fresh copy of Mozilla Firefox web browser or if you upgraded existing version of Mozilla Firefox to a new released version, you should definitely read this article.

What is Default Browser Agent in Mozilla Firefox Web Browser?

Newer versions of Mozilla Firefox web browser install a new tool or component called “Default Browser Agent“. It’s an executable with the name “default-browser-agent.exe” which is copied by Firefox browser to its program directory (C:\Program Files\Mozilla Firefox) at the time of installation or upgrade. It’s a feature exclusive to Windows operating system only.

Default Browser Agent’s EXE file is executed on daily basis via a registered scheduled task in Windows operating system. It’s a part of Mozilla Firefox’s telemetry and data collection feature. Default Browser Agent runs automatically every 24 hours whether Firefox is running or not.

When executed, it collects and submits following data from user’s device:

• Information related to computer system’s current and previous default browser settings. Information about the web browser that the user has set as OS default currently and the previous default web browser.
• Installed operating system (i.e. Windows) locale (such as en-US) and version number
• Firefox build channel (stable release, beta or nightly)
• Firefox version number

According to Mozilla, Default Browser Agent tool has been developed to help Mozilla understand user’s default browser settings. In future, it can be used to interact with users when they are not actively using Firefox (desktop notifications, may be?).

Should You Worry About Default Browser Agent?

Default Browser Agent is installed by all newer versions of Mozilla Firefox web browser. But it respects user’s telemetry settings configured in Firefox Preferences. If a user previously disabled or turned off all telemetry and data collection options present in “Privacy & Security” section of Firefox Options (about:preferences) page before upgrading to newer versions of Firefox, the Default Browser Agent respects user’s settings and doesn’t collect or send above mentioned diagnostic data to Mozilla servers.

In fact, if the user had data collection and telemetry options turned off, Firefox newer versions do not create and register any scheduled task to automatically launch Default Browser Agent every day.

But if you clean install Mozilla Firefox newer versions in a computer or you didn’t disable telemetry options in previously installed Firefox version, the setup will install and register Default Browser Agent task and the tool will collect and submit usage data to Mozilla.

How to Disable or Remove Default Browser Agent in Mozilla Firefox?

Don’t worry! There are many ways to completely disable or remove this Default Browser Agent feature installed by Mozilla Firefox web browser to protect your privacy.

You can follow below steps to get rid of Default Browser Agent tool and force it to NOT collect and send any data:

STEP 1: Turn Off Firefox Telemetry and Data Collection Settings

First of all disable all telemetry and data collection options given in Firefox settings. Once you turn off these settings, Default Browser Agent will stop collecting and sending data to Mozilla.

1. Open Firefox and click on the Hamburger icon present at the right-side end of the toolbar to open the main menu. Now click on Options menu to open Firefox settings page.

Alternatively, you can direct option this page using about:preferences command in address bar.

2. Now under “Privacy & Security” tab, scroll down to bottom and go to “Firefox Data Collection and Use” section.

3. Uncheck all given options under this section such as following:

• Allow Firefox to send technical and interaction data to Mozilla
• Allow Firefox to make personalized extension recommendations
• Allow Firefox to install and run studies
• Allow Firefox to send backlogged crash reports on your behalf

Now Default Browser Agent will no longer gather and report any data from your computer system.

STEP 2: Disable Default Browser Agent Using Hidden Preference/Flag

Mozilla Firefox also comes with a hidden preference/flag which can be configured to permanently disable Default Browser Agent feature.

1. Open Mozilla Firefox and type about:config in the addressbar and press Enter. It’ll show you a warning message, click on “Accept the Risk and Continue” button. It’ll open Firefox’s hidden secret advanced configuration page i.e. about:config page.

2. Now type browser-agent in Search filter box and look for following preference in the window:

The preference value is set to true by default, which means Default Browser Agent is activated and enabled in your system.

3. To deactivate and disable Default Browser Agent, double-click on default-browser-agent.enabled preference and set it to false. Alternatively, you can click on the Toggle icon given next to the preference name.

That’s it. It’ll immediately disable Default Browser Agent in your computer system.

STEP 3: Delete Default Browser Agent’s Scheduled Task

Since Firefox creates a scheduled task in Windows to automatically launch Default Browser Agent’s executable every day, it’s a wise idea to delete the task as well.

1. Press WIN+R keys together to launch RUN dialog box, type taskschd.msc and press Enter. It’ll open Task Scheduler.

2. Now click on “Task Scheduler Library -> Mozilla” in left-sidebar and look for following task in right-side pane:

3. Select the above mentioned task and press Delete key to delete it. Click on Yes button to confirm the action.

That’s it. Now Windows will never run Default Browser Agent automatically in background.

STEP 4: Prevent/Restrict Default Browser Agent Using Registry Editor

Mozilla Firefox also supports a policy which can be used to prevent or restrict Default Browser Agent from running and collecting any data. You can implement the policy using Registry Editor.

1. Press WIN+R keys together to launch RUN dialog box. Now type regedit and press Enter. It’ll open Registry Editor.

2. Now go to following key:

3. Create a new key under Policies key and set its name as Mozilla

4. Select Mozilla key and create another new key under Mozilla key and set its name as Firefox

So the final key path will be:

5. Select Firefox key and in right-side pane, create a new DWORD DisableDefaultBrowserAgent and set its value to 1

That’s it. It’ll disable Default Browser Agent feature in your device.

STEP 5: Block Default Browser Agent Using Firewall

If you want, you can block Default Browser Agent executable file from accessing and connecting to Internet using a Firewall program. Once you block the EXE file, it’ll be unable to connect to Internet and will not send any data.

Go to following folder:

Now look for default-browser-agent.exe file. Create a new rule in your Firewall settings to block this EXE file.

PS: You can also block pingsender.exe file from connecting to Internet using Firewall. This file is also present in same “C:\Program Files\Mozilla Firefox” folder. This is the main telemetry file which submits usage statistics data to Mozilla servers.

STEP 6: Delete or Rename Default Browser Agent Executable File

You can also delete or rename Default Browser Agent’s executable file. In this way, Windows will be unable to find the EXE file and will never run it. Since Default Browser Agent will not be able to run, it’ll be unable to collect or send any data.

Just go to above mentioned folder and delete or rename the file.

Also Check:

[Tip] Disable Automatic Background Updates Feature in Mozilla Firefox

[Tip] Disable Telemetry and Data Collection in Mozilla Firefox Web Browser

[Tip] Disable Recommended Features Suggestions in Mozilla Firefox

[Tip] Disable Recommended Extensions Suggestions in Mozilla Firefox