This article was been published more than a year ago. The information may be outdated.
My problems have, as I mentioned, been twofold; first there is the universal problem of not being able to add extensions, and second there is the problem of Firefox crashing on one of my machines.
The error data for the crashes look like this:
I decided to do a fresh reinstall of Firefox, but wanting to keep my profile, with all my bookmarks etc., I exported the profile folder (as detailed in the Mozilla Knowledgebase). I then uninstalled Firefox, and then reinstalled Firefox. I then imported the profile folder, and I am now able to install extensions, though the problems with the crashes remain. This seems to be caused by the profile, and I created a new profile accordingly.
To create a new profile, I ran the command “firefox.exe -ProfileManager”, and created a new profile. I copied files as detailed in the Mozilla Knowledge base article on recovering data from an old profile, and restarted firefox with the new profile, taking care to delete the old one. Some data was lost, but most of my preferences survived.
The install of Firefox was an updated and patched one, originally installed as 126.96.36.199 or something like that. Most likely problem was caused by my install of Firefox having been updated and patched instead of reinstalled.
To resolve this problem, I relied heavily on the following Mozilla Firefox Knowledgebase articles: