Your Firefox reported itself to be version 132, which isn't a supported release. Why Firefox 132??

To resolve the startup problem relating to XPCOM, you can try reinstalling using the following method:

(1) Download a fresh installer from

https://www.mozilla.org/firefox/all/desktop-release/

That will be Firefox 140.0.2

(2) Close Firefox and open Windows File Explorer and find this folder:

C:\Program Files\

(3) Right-click Mozilla Firefox and rename to OldFirefox

(Note: if Mozilla Firefox is not here, try looking in C:\Program Files (x86)\)

(4) Run the installer. It should detect and use your existing profile folder.

Any improvement?

Thanks for the reply. I don't use C: drive so the installer is unlikely to find the right files. I was hoping to be able to simply replace the appropriate file in a working version with the one from the crashed version, we just don't know which file(s) have the info.

Why Firefox 132?? We avoid downgrades because they often interfere with the working, e.g. loose tabs or simply crash as in this case. It appears someone managed to sneak a downgrade on us, and crash. Simple differences like not using C: drive will often crash the downgrades. As a programmer we are aware of the impossibility of anticipating the infinite setup possibilities. Our question would be why use Firefox 140?? On rare occasions different html coding requires changes to the browser, but otherwise there is no need to change. (For instance version 109 usually works, but cannot render a few sites correctly.) Before you start to talk about viruses etc, we should tell you that we have been using computers from before you guys were born, and have had only one virus in that time. That was a zero day virus (google wiki for definition), so no need to worry about viruses. The "solution" of downgrades that interfere with our work is far worse than the "solution". Best solution would be able to turn off downgrades. Does anyone know a way to do that reliably ?

> I don't use C: drive so the installer is unlikely to find the right files.

If you are custom installing Firefox in an alternate location, the process is the same: rename the folder and reinstall (using the Custom option: Custom installation of Firefox on Windows).

> Best solution would be able to turn off downgrades. Does anyone know a way to do that reliably ?

Firefox should never downgrade on its own. You do not need to turn off downgrades.

Firefox calls them "upgrades". I am sure you would agree anything that crashes a program or losses setups is a "downgrade". Does anyone know a way to turn off what firefox calls "upgrades" reliably ?