Firefox logo on a purple background

Private mode in Mozilla Firefox keeps your local browsing history private. But, by default, Firefox turns off extensions while browsing privately to prevent them from leaking data. If you’d like to use a trusted extension while browsing privately, it’s easy to turn it on. Here’s how.

First, open “Firefox.” In any window, click the “Firefox” menu button (three horizontal lines) and select “Add-ons” from the menu.

In Firefox, click the hamburger menu and select "Add-ons."

In a new tab called “Add-ons Manager,” you will see a list of all the Firefox extensions you have installed. Locate the extension you’d like to use in Private mode and click the ellipses button (three dots) beside it. In the menu that pops up, select “Manage.”

In Firefox Add-ons Manager, click the ellipses button and select "Manage."

After clicking “Manage,” you’ll see more details about the extension on a special page. Scroll down and locate the “Run in Private Windows” option. Click the radio button beside “Allow” to enable the extension in Private browsing mode.

Warning: Each extension you enable while private browsing will have access to your browsing data, which means the extension could capture that data and potentially share that data with a third party. Be sure you trust the extension before enabling this feature.

In the Firefox extension management page, select "Allow" for the "Run in Private Windows" option.

After that, go back to the last page and repeat these steps with any other extensions you might want to use in Private mode. When you’re done, close the “Add-ons Manager” tab.

The next time you open a Private window in Firefox, the extensions you enabled will be working as you’d expect them.

If you ever need to disable an extension in Private mode again, revisit the extension’s “Manage” page in the “Add-ons Manager” and select “Don’t Allow” beside the “Run in Private Windows” option. Good luck, and happy browsing!

RELATED: How to Always Start Any Browser in Private Browsing Mode

Benj Edwards Benj Edwards
Benj Edwards is a Staff Writer for How-To Geek. For over 15 years, he has written about technology and tech history for sites such as The Atlantic, Fast Company, PCMag, PCWorld, Macworld, Ars Technica, and Wired. In 2005, he created Vintage Computing and Gaming, a blog devoted to tech history. He also created The Culture of Tech podcast and regularly contributes to the Retronauts retrogaming podcast.
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