I use both systems. I can’t remember on which system I saw it happen. Personally I’m fine with relaunching immediately the browser. I just replied to give the information asked, but it seemed that somehow it made some people upset. I really don’t understand how and why, tough.

I find it irritating because one of the core principles of this kind of technology, to me, is that it should serve the user, not the other way around. I expect to be able to run the earliest version of windows 10 and go out to all sorts of virus-laden websites if I decide to. It's one thing to automatically download updates and let the user apply them when ready, but to actually disable the browser until the user complies is just unacceptable for me. Hence why I disable it.

I do applaud firefox for supporting so much customization, as in this case. If I weren't able to disable this behavior I would have stopped using firefox immediately.

Yeah, this is the exact kind of behavior that made me finally nuke my Windows install for good (although Adobe crap eventually forced me to dual-boot again). The irony of Mozilla copying Microsofts anti-features does not escape me and I sure hope this doesn't continue...

I for one am not upset, just confused because your information doesn't match my information.

I have seen it happen also, but it’s rare and I can’t recall if it was on Linux or windows. I tried to open a new tab and it said “no more tabs until you restart Firefox”.

I always assumed this was related to the multiprocess architecture. If you've updated Firefox in the background (e.g. via your package manager), and the new version is not API-compatible, it will not be able to create a content process for the new tab, hence the message.

Obviously this is only a problem on Linux, because on other platforms Firefox's own autoupdater will only apply the update when Firefox is restarting.

For what it's worth, that behaviour happens to me too (on a linux system), doesn't seem consistent though (but I never really took too much note).

Yeah, that's bound to happen on Linux if you run an update while Firefox is open. Being able to continue running while all your files get switched out from under you is a pretty big thing to ask from a program and I think they were having issues with crashes and risking corrupted profiles, so they made it do that just in case.

In my experience, running software updates while using the system is a pretty bad idea in general. It works well most of the time, but there's a reason Linux* is the only system that allows that (every other OS defers applying updates to a reboot).