Hello Martha08 On your Mac you have Activity Monitor. You can find it in this folder: /Applications/Utilities/ You can end the FF from there, just like the Task Manager on Windows computers Best Regards, JK

''Martha08 [[#question-1056767|said]]'' <blockquote> I now have 2 versions of FF running </blockquote> Two versions, or two entries in the program manager? Many users have reported problems with Firefox not closing properly. Do you have the Firefox icon on your quick launch? Right click on it, and select '''Open New Window.''' Sometimes this works. If it opens, close it by '''Menu > File > Exit.''' ------------------------ '''https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix''' '''https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding''' ------------------------- Start '''[https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Firefox in Safe Mode]''' {web Link} by holding down the '''<Shift><br> ''(Mac Options)'' ''' key, and then starting Firefox. Is the problem still there?