I always have 10 to 15 tabs open in 2 or 3 windows, so that is not the issue. Thanks anyway.

I think I may have finally found the problem: It only happens when I have Facebook open in a tab. No Facebook, no shutdown. I now run my Facebook session in Chrome, and it seems a bit more stable there. It's just a nuisance to have to have two browsers open. (Interestingly, if I open Facebook in Firefox and have it open in Chrome at the same time, then when Firefox dies, it takes Chrome with it!)

I hope this gets fixed soon, because I am not a fan of Chrome.

Hi JDHaviland, the Facebook news feed does impose a lot of stress on Firefox with its self-playing videos and endless scrolling. When you start up Firefox after that, did it behave as though it had crashed (goes into crash recovery) or does it behave as though you had shut it down normally? That could be hard to distinguish if you have Firefox set to restore your previous session tabs automatically...

It's quite rare that Firefox closes completely during normal browsing without a crash dialog of any kind. Over the years, I've seen a couple instances (probably in bug reports) where something about the HTML or CSS of a page overloads some part of Firefox and Firefox crashes silently. But if this were a widespread issue on FB, there probably would be a lot more reports. That makes me think of a problem with something user specific, such as particular photos/videos or personalized ads. Other than blocking things and seeing what happens, I'm not sure how to get to the culprit.

Is it just Firefox (or Firefox+Chrome) that crash and disapear, or is it the whole compuer or Operating Sytem crashing ? If that happens eiterh you get a Windows crash and the Blasck Sdreen Of Death, or the computrr crashes and restarts.

Overheating could be a problem and could cause the computer to suddenly shutdown.

John99, it is only the browser that just {poof} vanishes as if it was never there. Nothing else is affected at all. It has also happened to two of my coworkers. A bit of research with Google turned up evidence that this is happening to multiple browsers and to many people all over the world. There is a topic on it in Facebook's help forum: https://www.facebook.com/help/community/question/?id=10151770097773421&answer_id=10151779449533421&rdrhc

jscher2000, when I restart Firefox, it is as if it had crashed and it asks if I want to restore my previous session. No crashes have occurred in the 24 hours since I stopped including Facebook in a tab. Yesterday, I started running it in Chrome, because EVERY video in Facebook started to cause Firefox to hang solid, every time (It would run a bit, but I was only getting audio, then it would put Firefox into (not responding) and never come back). No idea why, but I had had it.