hello, could you provide your latest few submitted crash reports? please enter about:crashes into the location bar, copy the latest few report ids from there & paste them here into a forum reply. this will give us a better understanding what may be triggering those crashes.

Does it make a difference if you use "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: Firefox > Quit Firefox; Linux: Firefox/File > Quit) to close Firefox in case you are currently doing that by clicking the close X on the Firefox title bar?

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

You can also check for issues caused by plugins.

• https://support.mozilla.org/kb/Troubleshooting+plugins

Thanks philipp,

Here are the last 4.

bp-d1649659-2daa-41ca-a164-5e1a82140427
bp-1be1f8af-f607-411d-8583-e18622140426
bp-17ca1357-262c-4f8c-873b-ec9d02140426
bp-ca18e0a3-d5da-43d9-b53c-68f302140426

As I said in my question, Firefox isn't crashing and it doesn't happen every time. I have tried various ways of closing Firefox down. i.e.
Clicking exit cross at very top right of screen
Clicking File/Exit
Clicking Firefox icon at very top left of screen and then Close.

It happens with all of them, but I have just realised that it only happens when I have Gmail open, either as the only tab or as one of a number of tabs. I have just opened and closed Firefox about 20 times and it only happens when I have Gmail open.

Barry

Thanks cor-el,

I have tried various ways of closing Firefox down. i.e.

Clicking exit cross at very top right of screen Clicking File/Exit Clicking Firefox icon at very top left of screen and then Close.

It happens with all of them, but I have just realised that it only happens when I have Gmail open, either as the only tab or as one of a number of tabs. I have just opened and closed Firefox about 20 times and it only happens when I have Gmail open. If I close the Gmail tab down individually before I close Firefox the crash report doesn't occur.

As you know, I had a problem with an authentication notification on Gmail, which I solved by following your advice to delete my cookies.sqlite and permissions.sqlite files. I now believe the crash advice only started after that so is it related to me deleting those files?

Barry

You can try to set these two prefs to false on the about:config page to see if that has effect:

• media.windows-media-foundation.enabled
• media.directshow.enabled

This will disable the HTML5 media player for specific content (mp3, H.264).