After doing the software update with Ubuntu 16.04.2 with Raspberry pi 3. The firefox web browser version 55 is not working and crashed!
i have the same problem ...
I tried reinstalling Firefox running;
$ sudo apt --purge remove firefoxThen;$ systemctl rebootThen$ sudo apt install firefoxThen$ systemctl reboot
Firefox icon is on the top panel. Clicking it starts the same warning
I recommend you use the search facility on the forum - this thread is essentially the same as at least two earlier about the same problem.One has a workaround - install version 52, and hold that ; it works.Derek