Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

• switch to the Default System theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button in the Troubleshoot Mode start window

You can try to disable hardware acceleration in Firefox.

• Settings -> General -> Performance
  remove checkmark: [ ] "Use recommended performance settings"
  remove checkmark: [ ] "Use hardware acceleration when available"
• https://support.mozilla.org/en-US/kb/performance-settings

Close and restart Firefox after modifying the setting to apply changes.

• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Hello;

Thanks for your reply. In the interim I stumbled upon a solution, I think. I started to explore Multi-Account Containers and set up Work, Personal, etc. When I use either of these containers, all tabs behave as they should with no crashing. So whenever I search with Google, if I use these containers, everything works fine.

Well, I've tried the solution proposed to Troubleshoot mode and to disable hardware acceleration. Also cleared cache totally, and whenever I'm using Google to search in a new window, I'm still getting "Gah, your tab crashed". So now, I've wiped out all my open tabs, all history, and I'm still NOWHERE.

The only way I can get a Google search to complete is by using a Container Tab. However I cannot find a way to get a Container Tab to open by default in a new window. So, in order to function, I first need to open a new window, THEN remember to open a new container tab. I have been using Google in Firefox for many years and I can't always remember that I have to jump through this hoop.

So what's the solution??? If no one can suggest anything more it seems to me I have to change my default browser from Firefox to Chrome.....  ????

Hi,

Sorry to hear about your issues with Firefox on Big Sur. Since it works in private browsing, try these steps:

Clear cache and cookies: Preferences > Privacy & Security > Clear Data. Refresh Firefox: Help > More Troubleshooting Information > Refresh Firefox. Create a new profile: about: profiles > Create a New Profile. Disable hardware acceleration: Preferences > General > Performance > Uncheck Use hardware acceleration. If these don't help, consider reporting the bug to Mozilla. Hope this helps!

Regards

You can remove all data stored in Firefox for a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History -> Show All History" or "View -> Sidebar -> History").

Using "Forget About This Site" will remove all data stored in Firefox for this domain like history and cookies and passwords and exceptions and cache, so be careful. If you have a password or other data for that domain that you do not want to lose, make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of involved files.

If you revisit a 'forgotten' website, data for that website will be saved once again.

• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox

Thanks for both replies, but as it turns out I have solved my own problem. Unless this problem is unique to me, it may benefit someone else. I noticed that I did not have a tab crashing when I used a container tab, such as personal, work, etc. However as soon as I searched with Google I had a crash. I was searching around on Extensions and came across a Google Container. I installed it, and now the problem has vanished. I see this is not an official addon from Mozilla, but it has solved my problem (which took hours of searching) so I can get back to work. Thank you.

Well, that solution (with containers) was working, now it's not. I have no idea why. I keep updating Firefox when new version is available, hoping things will improve, but they do not. I am now running 129.0.1.

Is this because I am using an older Mac (late 2014) and running 11.7? (I cannot update the OS any more). If this is so, I have no choice but to delete Firefox from my Apps and go with another browser. I am exhausted, and I can't function without being able to search with Google.

You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

If the new profile works, you can transfer files from a previously used profile to the new profile, but be careful not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile