In the address bar, type about:crashes<enter>. Note: If any reports do not have BP- in front of the numbers/letters, click it to submit them.

The crash report is several pages of data. We need the report numbers to see the whole report.

Using your mouse, mark the most recent 7 - 10 Submitted crash reports, and copy them. Now go to the reply box and paste them in.

Please, Do not post a screenshot ! !

For more help on crash reports, see; https://support.mozilla.org/en-US/kb/firefox-crashes-asking-support

The latest crash report is 2018 - so there is no report for my problem. Firefox definitely exited, then when I restarted it I was asked whether I wanted to resume or to start afresh.

Make sure that you have updated to Firefox 81.0.1 as that version has some fixes.

• https://support.mozilla.org/en-US/kb/update-firefox-latest-version
• Help -> About Firefox

I am running 81.0.1 already. This has been a problem for at least 6 months.

Do you only have tab crashes because Firefox doesn't send a report for such tab crashes ?

You can check the Firefox Task Manager (about:performance) and about:memory pages.

• https://support.mozilla.org/en-US/kb/task-manager-tabs-or-extensions-are-slowing-firefox
• https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-or-cpu-resources

I checked the Firefox memory allocation and the main process was using ~200MB. I then used the offending site - Firefox fired up audiodg.exe and as I played its memory allocation increased by 20MB at every beep. I continued until the memory allocation for process audiodg.exe had reached 2GB - the Firefox memory allocation was unchanged.

I repeated the test with Chrome, which also fired up audiodg.exe but its memory allocation remained constant, with no change at each sound effect.

There are more such reports of issues with audiodg.exe.

• https://www.google.com/search?sa=N&num=100&q=audiodg.exe%20memory%20leak

Yes, I have seen those. It seems that audiodg.exe is a long-standing utility. It is obviously called by both Firefox and Chrome. But the Firefox implementation appears to be faulty and allowing a memory leak.

I will test it again on another PC just in case it is peculiar to my machine!

I see a report that might indicate that this also can be a problem with settings in the sound card.

That was helpful. I tried a few sound settings and got inconsistent behaviour. I also tested on another PC and the problem did not occur. So it must be something about my system. Strange it appears with Firefox but not Chrome. At least I have a workaround!

Thanks for the prompt replies.