How to Downgrade Firefox

Last Updated: April 30, 2021 Tested

This wikiHow teaches you how to return to an older version of the Firefox web browser on your computer. Mozilla, the organization that develops Firefox, offers downloads of all previous Windows and macOS versions for testing purposes—they do not, however, recommend downgrading, as older version usually have unpatched security holes. Mozilla doesn't offer older versions of the Firefox mobile app for download.

Steps

1
Find out which version of Firefox you have now. If you're having trouble with Firefox and want to go back to the version you had before, you'll first need to figure out which version you have now. To find your version:
- Open Firefox.
- Click the menu with three horizontal lines at the top-right corner.
- Click Help.
- Click About Firefox.
- The version number appears below "Firefox Browser" in the window (e.g., 86.0 64-bit).
- Write down the full version number so you don’t forget it.
2
Go to https://ftp.mozilla.org/pub/firefox/releases/ in a web browser. This is the FTP link that archives all versions of Firefox that you can still install.^{[1]
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Research source}

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3
Select the Firefox version you want to install.
- For example, if you want to downgrade to version 86, you'd click 86.0.
- Versions with a lowercase "b" in the name are beta versions.
4
Click the folder for your operating system. The folders here don't always have the most straightforward names, so use these tips to help you make the right selection:
- Mac: This one is actually straight-forward—click the folder called mac.
- Windows: Look for "win32/" (32-bit Windows) or "win64/" (64-bit Windows) in the link text. Make sure you choose the same bit number 32 or 64 you saw in your version number.
5
Click the language folder. The list on this page is abbreviated regional languages.
- For example, if you speak English and are in the United States, you would click the en-US folder.
6
Click the download link. If you're using Windows, choose the link that ends with ".exe." If you have a Mac, choose the one that ends with ."dmg." This downloads the installer to your computer.
- Depending on your browser settings, you may be prompted to confirm the download or select a location to save to before the download will begin.
7
Uninstall the current version of Firefox. Here's how:
- Windows
  - Press Windows key + S to open the search bar and type add remove.
  - Click Add or remove programs.
  - Scroll down and select Mozilla Firefox.
  - Click Uninstall and follow the on-screen instructions.
- Mac
  - Open Finder and click the Applications folder.
  - Drag the Firefox icon to Trash.
8
Disconnect from the internet. Firefox includes a security feature that installs the latest security updates in the background. To prevent Firefox from automatically updating itself to the newest version, you'll need to disconnect from the internet before installing the downgraded version. You can simply disable your Wi-Fi or remove the Ethernet cable from your computer after the installation file is finished downloading.
9
Double-click the Firefox setup file to Install Firefox. You will find it in your default Downloads folder. Follow the on-screen instructions to install Firefox. When it's finished installing, it will launch for the first time.
- On a MacOS Sierra and later, you may have to manually allow the installation before continuing.
10
Create a new profile. As of version 67, Firefox now has downgrade protection, which requires you to create a separate profile from the one you used in the most current version.^{[2]
X
Research source} You just won't be able to use them in the downgraded version. Click Create New Profile when prompted and follow the on-screen instructions to set up a new profile.
- Don't worry, you won't lose your bookmarks or other profile info, which will still be available once you upgrade to the latest version.
11
Disable automatic updates as soon as Firefox launches. Firefox is set up to update automatically in the background so you always have the latest security patches. If you want to keep your downgraded version, you will need to turn this feature off. Here's how:
- Click the three-line menu at the top-right corner and select Options.
- Scroll down to the "Firefox Updates" section.
- Select Check for updates but let you choose to install them.
- Remove the checkmark from "Use a background service to install updates."
12
Reconnect to the internet. Now that you've downgraded to an older version and disabled automatic updates, you'll be able to use your downgraded version as long as you'd like.

Community Q&A

Question

I play on a game site and some of the games are still in Java. Firefox (prior to v42) was the only browser that worked. Tonight it upgraded itself. I did what the article said, but still can't play. What now?

Community Answer

Have you considered upgrading your Java version? In many cases, the reason certain browsers work is due to its compatibility with your Java version. You should be able to update it in "System Updates" on your computer.
Question

Installed 62.0 ESR, disabled browser updates, added some add-ons, closed browser. Relaunched browser which proceeded to automatically update 62.0 ESR to the dreadful Quantum browser. Any workaround?

Arrogance

Top Answerer

Firefox 62 is Quantum. Everything from 57 on up is the Quantum codebase. Also, 62.0 is not an ESR release. That was 52.

Warnings

Older Firefox versions often contain unpatched vulnerabilities which can be exploited by attackers to infect your system with malware and steal your personal information. Be careful when using an older Firefox version.

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