We're sorry to hear that Firefox is crashing when you open it. Please do the following to give us crash IDs that will help us understand more about the crash.

1. Click the Finder' icon in the dock. On the menu bar, click the Go menu, hold down the option or alt key and select Library. A window will open containing your Library folder.
2. Open the "Application Support" folder, the "Firefox" folder, the "Crash Reports" folder and finally the "submitted" folder.
3. Open the 5 most recent files with a text editor and copy the IDs.
4. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Hi Paul Sorry about the delay in getting back to you. Thank you for your advice which I have followed.

Unfortunately, I did not get very far at all. After what appears to be a normal download and app installation process I end up with a Firefox app in the "Applications" folder, a Firefox folder in the "Support" folder and a "Firefox" drive icon on the Mac screen - I can eject the icon as it appears in Finder. I am not getting any response at all when I attempt to start the Firefox app from any of these sources and there are no fault reports produced. There is no "Submitted" folder in the Firefox "Application Support" folder so I am not getting as far as a recognised "crash" in the first instance apparently. As I mentioned earlier all the apps installed prior to this issue still appear to be working normally, touch wood. It suggests that "Firefox" is not being recognised as an app as far as macOS is concerned.

I am concerned that I may have picked up a security problem on the Mac in general although both Bitdefender and Malwarebytes continue to report no identified security issues.

Any ideas on where I should go from here? I do have an Acronis Cyber Protect Home Office Recovery disk from before this issue arose so I am wondering if I should forget trying to "fix" the problem and just attempt a recovery of the Mac from the Acronis disk. I am not sure if an Acronis recovery would wipe out any more recently introduced security bug that might have infected the Mac but I could clarify that with Acronis if you think that I have hit a brick wall on this one in addressing it as just a Firefox issue?

Hi Paul A note to my last message. Part of my Acronis package is a "Protection" package which I forgot I had running in the background. I thought I had it stopped some time back because it seemed to be superfluous to Bitdefender and Malwarebytes and seemed to be slowing the Mac down. I also use NordVPN full time.

For whatever reason Acronis "Protection" appears to have still been operating and, while still with 12 hours to go in its latest scan, reports a "Ransomware" threat in the Firefox Applications file path possibly accounting for my problem as the quarantining of the threat file occurred about the same time as my Firefox issue. I have attached a copy of the relevant Acronis screen shots for your information.

The threat reference is: 59c69a255e6644742a3d53b3c812e6f4 SHA1 is: 41fc085bdb1ac53dbfd274f4ee91a38778ad70e0 SHA256 is: e07de43f41be605fa33395e4ce97963793e9782ff8f6809e525273d6b4562a9b

As I always use the Mozilla Firefox and Thunderbird websites to get installation files there remains a possibility that the threat file came in via one of those websites. The only qualification to that is when the issue became apparent I had not had such a download for a long time. So the source is really unknown.

It appears that with Acronis Protection quarantining the Firefox app folder neither Bitdefender nor Malwarebytes would be unable to see the threat file and the app was not able to be run by macOS.

I will let the Protection scan run its course and then let you know of any further detections.

Hi Paul Having again removed a non-responding Firefox app after each recovery I now have completed several macOS Recovery sessions, from the Mac built-in source and from the internet. Bitdefender, Malwarebytes and Acronis Protection reported no security issues with the Mac following all recoveries. In addition, all other apps from the pre-Firefox issue continue to run normally. Apple Hardware/Diagnostic tests have not revealed any issues. Re-installing Firefox always ends with a non-responsive Firefox installation and no recorded Crash reports - the installation is clearly in the Applications folder but doesn't elicit any response when clicked on there or in the dock?

Apart from the option to erase the startup disk using the Mac Disk Utility followed by reinstalling macOS and recovery of my personal files from an external disk I don't seem to have any other remedies to try? Any further thoughts or suggestions before I nuke my Mac's SSD and start from scratch again?

Hi Paul I have downloaded the latest Firefox app (Firefox 109.0.1.dmg) and am holding it in Downloads until I finish security checks (Bitdefender, Malwarebytes, Acronis Protection) prior to attempting an installation. I'll let you know the outcome in due course.

Hi Paul Exactly the same outcome as before - no go! The installation went quite normally until I tried to open the app - then, only advice that the a"app" could not be opened - end of story!

Hi Paul Only 3 outcomes seem likely - First: There is a fault in the Mozilla Firefox download files, - Second: There is a fault in the downloaded macOS system files used to recover the system, and Third: There is a security problem or missing file on the Mac Data disk that is unrecognised by Bitdefender, Malwarebytes and Acronis Protection.

At this time I am putting my money on some sort of missing instruction set/security issue lurking on the Data disk. Consequently I am starting to set myself up to erase the Mac Data disk completely before proceeding to a new OS install and recovery of my user files etc.

Any comments or suggestions?

Hi Paul As I am unable to solve this issue after days of effort and frustration I have reluctantly decided to give up trying to reinstall Firefox Firefox and remain with Safari - at least it works. Chrome also seems interesting so I might give it a try. Thanks for your initial advice.