Hi derek16, your browser user agent might be disguised if you set privacy.resistFingerprinting to true in about:config. Otherwise, that is hard to explain.

Could you download a copy of this article for reference in the next steps:

How to stop Firefox from making automatic connections

Then, could you test what happens when your computer has no network connection at all: cable disconnected, wi-fi disabled, etc. Does Firefox still behave badly or is it calm?

If Firefox is calm when it's "offline," check through the settings article and see whether there are any things you might want to try disabling.

Hi, thanks for the advice. I did restore the correct user agent by changing the privacy.resistFingerprinting setting back.

I disabled all of the background connection settings in FF, and it then ran stable. Now I have been re-enabling them one at a time, running FF for a while between each change, to see which one causes it to freeze.

I'm still perplexed how one of the FF settings can result in the entire machine freezing...there is no core dump either.

Once I can determine the faulty setting, I'll post it back to this thread.

Update on the issue.

I am still seeing FF70 hang, and cause the whole system to hang as well. It is not as often as previously observed.

I have followed the troubleshooting advice, going through the steps of disabling background activities; clearing out the places database; disabling extensions and addons; and monitoring memory usage.

I monitor CPU and memory usage, and neither are spiking at the time of the freeze. I even monitored "about:performance" and "about:memory" and nothing unusual is happening.

There is no core dump being generated, as the process isn't crashing.

I need to take this investigation to the next level. Could someone please advise what that would be?