Are you quitting firefox before shutting down your mac or just closing it?

I always close all opened programs before shutting down and never choose the close down option to reopen all windows upon restarting. Having Firefox opening at startup slows down the start up process. This only started a short time ago probably after one of the recent Firefox updates.

I don't think Firefox adds itself to the startup sequence on any OS.

Is there any place you can check what is set to start up automatically on your Mac and remove Firefox from there? Or perhaps it's a URL that MacOS sends to your default browser at startup?

See also:

• https://support.mozilla.org/en-US/kb/Firefox launches automatically when your computer starts#firefox:mac

https://support.mozilla.org/en-US/kb/Firefox Page Not Found

Try this link: https://support.mozilla.org/en-US/kb/firefox-starts-automatically-when-i-restart-window#firefox:mac:fx54