What changing your default browser means

Your default browser is the program that opens automatically when you click a link in an email, a document, or anywhere else on your computer. If Firefox is installed but not set as default, Windows or Mac will open links in a different browser instead — usually Edge on Windows or Safari on Mac.

Changing the default to Firefox means Firefox will open those links from now on. This is a one-time change you make in Firefox's settings, and it takes about two minutes. The steps differ slightly between Windows and Mac, but both are straightforward.

Key Takeaways

  • Your default browser opens automatically when you click links outside of Firefox, and you can change it to Firefox through the Settings menu.
  • On Windows, you can also set Firefox as default directly from Windows Settings, which sometimes works faster if Firefox's own setting does not stick.
  • On Mac, the process is in System Settings under General, not in Firefox itself.
  • If Firefox does not appear as an option, make sure it is fully installed and that you have restarted your computer since installing it.

Changing the default browser on Windows

Open Firefox and select the menu button (three horizontal lines) in the top right corner. Click Settings, then click General in the left sidebar. Scroll down to the Startup section and look for the button that says Make Default. Click it.

A Windows dialog will appear asking you to confirm. Click Yes or Switch Anyway — the exact wording depends on your Windows version. Firefox is now your default browser. Any link you click outside Firefox will open in Firefox from now on.

If the Make Default button is grayed out or does not appear, Firefox may already be set as default. If you clicked it but links still open in a different browser after restarting your computer, try the Windows Settings method instead: go to Settings > Apps > Default Apps, scroll to Web Browser, click the current default, and select Firefox from the list.

Changing the default browser on Mac

On Mac, you change the default browser through System Settings, not through Firefox itself. Click the Apple menu in the top left corner and select System Settings. Click General in the left sidebar, then scroll down and click Default Web Browser.

A dropdown menu will appear showing all browsers installed on your Mac. Click Firefox to select it, then close System Settings. Firefox is now your default browser. If Firefox does not appear in the dropdown, restart your Mac and try again — sometimes the system needs to refresh its list of installed programs.

What to do if Firefox does not appear as an option

If you do not see Firefox in the default browser list on either Windows or Mac, the most common reason is that Firefox was not fully installed or the installation was interrupted. Restart your computer first — sometimes the system straightforward has not recognized the new program yet.

If Firefox still does not appear after restarting, uninstall Firefox completely, restart again, and reinstall it from mozilla.org. read the installer for your operating system, run it, and follow the prompts. Once installation finishes, restart your computer one more time before trying to set Firefox as default.

Checking that the change worked

To confirm Firefox is now your default browser, open an email or document on your computer and click any link. Firefox should open automatically. If a different browser opens instead, the change did not stick — go back to the settings and try again, or restart your computer and repeat the process.

On Windows, if restarting and repeating the Firefox setting does not work, use Windows Settings instead (Settings > Apps > Default Apps > Web Browser). On Mac, if the change does not stick after restarting, open System Settings again and confirm Firefox is still selected in the Default Web Browser dropdown.

Changing it back if you want a different default

If you decide later that you want a different browser as your default, the process is identical. On Windows, open that browser's settings and click Make Default, or use Windows Settings. On Mac, go to System Settings > General > Default Web Browser and select a different browser.

You can change your default browser as many times as you want. There is no limit, and changing it does not uninstall or affect the other browsers on your computer — it only changes which one opens links automatically.

Frequently Asked Questions

Will changing my default browser affect my bookmarks or passwords in other browsers?

No. Changing the default browser only affects which program opens when you click a link. Your bookmarks, passwords, and data in other browsers stay exactly where they are. Each browser keeps its own separate information.

Can I set Firefox as default for some links but not others?

No. The default browser setting is all-or-nothing — whichever browser you set as default will open all links from outside that browser. You cannot choose different defaults for different types of links or websites.

What if I want Firefox to be default but I also want to use another browser sometimes?

You can keep both browsers installed and use whichever one you want by opening it manually. Setting Firefox as default just means links will open in Firefox automatically — you can still click the other browser's icon whenever you want to use it instead.

Does setting Firefox as default change anything about how Firefox works?

No. It only changes what happens when you click links outside of Firefox. Firefox itself works the same way — your settings, extensions, and browsing experience do not change at all.