User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Firefox/45.0 Build ID: 20170411115307 Steps to reproduce: Installed Firefox 53.0.2 Configured radio button in "Options >> Advanced >> Update" to "Never check for updates (not recommended: security risk)" Actual results: About dialog popped up on its own and indicated an update had been downloaded, 53.0.3, and would be installed when I restarted FF. Expected results: Firefox should have behaved as one would expect from the UI configuration, which is to *never update*. Why have that option if it has no impact? It's misleading. I had to manually delete the updated directory. For now I've disabled and then uninstalled the maintenance service. I didn't even know there was such a service - why was I not prompted whether I wanted to install this when installing FF? Why do I have to uninstall it to get FF to do what's expected from its UI configuration? I thought Microsoft was bad with its dumbed down "Windows Update" service that forces updates down your throat, but looks like FF is following the same pattern. I can make my own decisions.

If the pref was changed after the download started the download will continue. Could you try to reproduce and only use a profile that6 already has it set to not update? Thanks!

I have been experiencing that for a long time throughout multiple versions of Firefox. In the Options the radio button "Never check for updates" has always been checked, but Firefox kept ignoring it and updating itself without ANY notification - I simply close it in the evening, run it again next day and a new version starts. There is no notification at all that a new version has been installed. Very annoying, especially if a new version is broken and makes using Firefox even more difficult than before.

BTW, I reported that bug 2 years ago and nothing has been done about it. Bug number: 1244516.

I can confirm this bug on Windows.

I have seen many people talking about this on Twitter, and some say the culprit is Kaspersky that automatically upgrades Firefox (and probably other outdated applications) regardless of the update settings.

(In reply to Kohei Yoshino [:kohei] from comment #5) I'm using ESET Internet Security and Firefox downloads the updates to its Updates folder and executes the upgrader next time I run Firefox.