This been asked already in "How to never check for updates in version 63.0b4? | Firefox Support Forum | Mozilla Support" https://support.mozilla.org/en-US/questions/1232918 but the ticket was closed without having been properly answered -- and I feel that the people who replied at the end of the thread were taking the piss (why is it saying "Flash Plugin", that's not what the ticket was about?!). (+ NOTE: I understand 100% Artmaker's frustration and anger back there.) I am doing automated testing using Firefox (and Selenium) and those automated updates are huge problem for me. I have disabled the automated update but the prompt is still being an annoyance: it causes my application-under-test to crash. I shall stress that being unable to disable this message is not acceptable! Have I made myself clear? And if that's the case, I would very much like to escalate this to Firefox developers, because I've been struggling with this problem for way too long. Thank you, P.