Firefox and Thunderbird periodically crash, won't start again until rebooting

My mother has been experiencing a severe issue on her computer for several months. After I got her a more performant motherboard today, the issue seems to have worsened rather than improved. I can’t find any useful information to debug this problem, so I’m hoping someone else might have an idea about what is going on with her machine.

The issue only seems to affect software from Mozilla, namely Firefox and Thunderbird. After a few minutes of uptime, either Firefox or Thunderbird (usually the first) will crash, bringing up a popup that asks whether I wish to submit a crash report to Mozilla. Once a crash has occurred, the affected program will no longer start up until the computer is rebooted: The crash will now occur immediately as you try running the application. I’ve verified that no older process copies of the program are still running, tried a fresh profile and running in safe mode, and even logging out and back doesn’t fix it!

When running FF or TB from a console once they become affected by the crash, I only see the following lines before I get the crash popup:

ExceptionHandler::GenerateDump cloned child 2855
ExceptionHandler::SendContinueSignalToChild sent continue signal to child
ExceptionHandler::WaitForContinueSignal waiting for continue signal...

Does anyone have an idea of what might be happening? Why would Firefox / Thunderbird periodically crash for no reason, and most importantly what does it change in that session that causes them to no longer start up until the computer is rebooted?

I have not seen any Thunderbird crashes. But perhaps that’s because I don’t use it very much.

Firefox is crashing more often than I used to see with older firefox versions. And it is also using a lot more memory. Those are probably related.

You should not need to reboot to start firefox. That suggests that part of the previous firefox is still running. Current firefox seems to use several processes. When it crashes, perhaps some of those processes are still running. Maybe check with the “ps” command – something like

ps -ef | grep firefox

Especially now that I upgraded her computer from 4GB to 8GB of RAM, memory is no longer a problem. It was doing this less when the machine had fewer memory, and I’ve already monitored all system parameters on crash… clearly that isn’t the issue.

I will try that command tomorrow once I see it happening again, and see if I can find any relevant processes I can kill to restore the program for that session. Thanks for the suggestion!

A heads up: I found at least part of the reason why Firefox / Thunderbird were crashing, followed by other applications today including the whole system. It appears one of the RAM modules was absolutely wrecked; I’ve ran memtest and found it was spewing a dozen errors per second! I removed two bad DDR2 modules in total, and the issue hasn’t occurred again since. I didn’t imagine the memory might have gone bad and was focusing on a software issue. I’ll bump this if I notice it again and bad RAM wasn’t the only cause.

Yes, bad memory can cause such crashes.

However: may I suggest that you put those memory modules back and test again to see if you are still getting errors. Sometimes the errors can be due to the modules not being properly seated in their sockets.

I tried the faulty one in several sockets. Sometimes it wouldn’t even light up the monitor due to how broken it was. I marked the bad modules to know they’re broken and left the machine with just two good ones for now.

Fair enough. That seems a convincing test.