When you uninstall Mozilla Firefox from your Mac, you have the option of removing only the application or removing the application and the user account information. Uninstalling only the Firefox application means that if you reinstall Firefox, all of your previous bookmarks, menu items and personal preferences will return. Uninstalling both the application and the account information erases all Firefox information. If you reinstall the application, it will have the default settings.
Instructions
Go to the "Applications" folder in the Finder.
Click on "Firefox," drag it to the Trash and drop it. If you only want to uninstall the application, skip to Step 5.
Click on the "Go" menu and select "Home." Open the "Library" folder. Open the "Application Support" folder. Open the "Firefox" folder. Open the "Profiles" folder.
Click on the folder with the ".default" extension. Drag it to the Trash and drop it.
Go to the "Finder" menu and select "Empty Trash." Confirm the selection in the pop-up window.
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