I've been struggling with this issue for a few months. After Firefox updates, my toolbar layout gets reset and I have to re-do it from scratch. If that wasn't bad enough, occasionally when this happens it also enters this state where nothing loads. All tabs just get stuck in blank screen "dancing dot mode". Yes, google, everything. To "fix" this, I go into troubleshoot mode, and back to normal again, and then it's "fixed"... until it happens again a few days later. I can actually rebuild my toolbar layout in under 15 seconds now, I've done it so many times. I've tried doing the 'refresh'. Many times. I've fully uninstalled and re-installed Firefox. I uninstalled plugins that I suspected might be the cause. Nothing worked. At best these measures kept firefox stable a couple of weeks longer. I actually gave up and tried other browsers for a while. Any insight is appreciated.