On the Dock, right-click the trash icon and select Empty Trash.

Find the Firefox icon, right-click that icon, and select Move to Trash in the pop-up menu.

On the left side of the Finder window, click the selector in the Favorites section.

Click the Finder icon on the Dock at the bottom of the screen.

Press the control key and click anywhere in the Finder window, and select Eject 'Firefox' in the pop-up menu.

Drag the Firefox icon in the Finder window to the Applications folder to copy the Firefox application to that folder.

If it does not, click the Firefox.dmg downloaded file in your browser, which should open Finder.

After the download completes, Finder should open and display the Firefox application.

Open your Safari browser and access the Mozilla Firefox download page.

Safari is the default Internet browser for macOS. To install or uninstall Mozilla Firefox on your macOS computer, follow the steps in the applicable section below.

Click the Uninstall/Change option above the list of programs.

Find and select the Mozilla Firefox program in the list.

Under the Programs section, click the Uninstall a program link.

Open the Control Panel or press the Windows key, type Control Panel, and then press Enter.

In Microsoft Windows, click the Firefox icon, or if the Firefox icon is not seen, click Start and type Firefox. Once Firefox is installed, it's run like any other program installed on your computer.

Once the download has completed, click Run or the downloaded file itself (usually in the lower-left corner of your browser window).

Click the Download Firefox button on the page.

Open your Internet browser and access the Mozilla Firefox download page.

Edge is the default Internet browser for Microsoft operating systems.

Reinstall firefox