I do not understand the Crash Report but no one else has answered yet. I do see flashplayer is involved so you could consider uninstalling flashplayer to see if that helps. Because it is a startup crash you may well need to do a clean reinstall of Firefox to get it working. That involves deleting the Firefox Program files before reinstalling Firefox *[[Firefox keeps crashing at startup#w_try-a-clean-install]]_try-a-clean-install <br/> Make sure it is the Linux version of the article you read direct link https://support.mozilla.org/en-US/kb/firefox-keeps-crashing-startup#firefox:linux:fx50 On Linux I often have both the Distro version of Firefox (Canonical on Ubuntu & IceWeasel on Debian) Installed. as well as the Mozilla Build of Firefox. If installing the Distro version does not work maybe consider installing the Mozilla build of Firefox * See [[Install Firefox on Linux]] * & https://help.ubuntu.com/community/FirefoxNewVersion/MozillaBuilds