1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the Advanced panel, click the General tab, and then click Make Firefox the default browser.

   

   • If Firefox still isn't the default browser, see Setting Firefox as the default browser does not work - What to do.
3. Close the Settings page. Any changes you've made will automatically be saved.

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the Advanced panel, click the General tab, and then click Make Firefox the default browser. The Set Default Programs window will open.

   

3. In the Set Default Programs window, select Firefox from the list of programs on the left and click Set this program as default. Then click OK to close the window.

   

4. Close the Settings page. Any changes you've made will automatically be saved.

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the General panel, and then click Make Firefox My Default Browser.

   

   • If Firefox still isn't the default browser, see Setting Firefox as the default browser does not work - What to do.
3. Close the Settings page. Any changes you've made will automatically be saved.

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the General panel, and then click Make Firefox My Default Browser.

   

3. The Set Default Programs window will open.
4. In the Set Default Programs window, select Firefox from the list of programs on the left and click Set this program as default. Then click OK to close the window.

   

5. Close the Settings page. Any changes you've made will automatically be saved.

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the General panel, and then click Make Default.

   

   • If Firefox still isn't the default browser, see Setting Firefox as the default browser does not work - What to do.
3. Close the Settings page. Any changes you've made will automatically be saved.

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the General panel, and then click Make Default.

   

3. The Set Default Programs window will open.
4. In the Set Default Programs window, select Firefox from the list of programs on the left and click Set this program as default. Then click OK to close the window.

   

5. Close the Settings page. Any changes you've made will automatically be saved.

Based on information from Default browser (mozillaZine KB)

Use the Settings app to change your default browser

You may see the following error message if you try to change your default through the Firefox menu: To change your default apps, go to Settings > System > Default apps.

Click OK to close the error message and follow these steps:

1. Go to the Start menu and click the Settings icon.
2. Click System, then choose Default Apps on the left pane.
3. On the right, scroll down to Web browser section and click on its entry.
4. A dialog will open with a list of browsers. Scroll down to Other Options, where you'll see Firefox listed.
5. Click Firefox.
6. The Web browser section will now show Firefox as your default.
7. Click the X to close the Settings window. Your changes will be saved automatically.

1. Click the menu button The image "new fx menu" does not exist., then choose Options.
2. In the General pane, click Make Default.

   

3. The Windows Settings app will open with the Choose default apps screen.
4. Scroll down and click the entry under Web browser.

   

5. A dialog will open with a list of available browsers.
6. Scroll down to Other Options, and click Firefox.

   

7. The Web browser section will now show Firefox as your default.
8. Click the X to save your changes and close the window.