If you're experiencing issues with Firefox on your Apple computer, you can follow these steps to shut it down and restart it: '''Force Quit Firefox:''' * Press Command + Option + Esc to open the "Force Quit Applications" window. * Select "Firefox" from the list. * Click "Force Quit." '''Verify Firefox is Closed:''' * After force quitting, make sure Firefox is completely closed. You can check by looking for the absence of the Firefox icon in the Dock. '''Restart Firefox:''' * Open Firefox as you normally would. If the issue persists, you can also try these additional steps: '''Check Activity Monitor:''' * Open "Activity Monitor" from the "Utilities" folder in the "Applications" folder. * Look for any Firefox processes in the list. * If you find any, select them and click the "X" button in the top-left corner to force quit. '''Restart Your Computer:''' * Sometimes, a simple restart of your computer can resolve unexpected issues. '''Safe Mode (Optional):''' * You can try starting Firefox in Safe Mode to see if any add-ons or custom settings are causing the problem. To do this, hold down the Option key while starting Firefox, and then select "Start in Safe Mode."

See also: *https://support.mozilla.org/en-US/kb/Firefox-already-running-not-responding