Re: Firefox has frozen on my I Mac, I am unable to quit Firefox so that I can shutdown my computer, can you please help me ?
Welcome to Mozilla Support!
There are a couple of things you can try to fix this follow the steps, if one works, then you are done
1 Try to double-click/ctr-click the firefox icon and select "Quit".
2 Try to press the force-quit shortcut cmd+q
3 Use activity monitor (cmd+space -> "activity monitor" -> enter) From here, locate Firefox and click the "X" in the to left corner.
4 Open Terminal (cmd+space -> "terminal" -> enter) From here search for the Firefox Appliation using "ps -ef | grep firefox". Now you are presented with hopefully just one or two items named firefox. They have a 4 digit Pid Number. Then write "kill -9 Pid" (where pid is the number from the application).
edit: to simplify the quit through terminal process, you can simply write "kill -9 $(ps -x | grep firefox) ".