When I close a video site tab, Firefox freezes and becomes unresponsive. After restarting Firefox from a force quit, I sometimes see a message like: “Bookmarks may not be visible or things may not look normal. Another instance of Firefox is running.” (I don’t remember the exact wording.) In that case, my bookmarks look like they are missing. If I close Firefox again and restart it, the bookmarks reappear, but I am logged out of every site and have to add all my accounts again from the beginning. This means I have to log back into every single account again, like YouTube and others, which is very inconvenient. I’ve been using Firefox for over 10 years, and I’ve never experienced this problem before. It doesn’t happen all the time, but it occurs periodically — sometimes every few days, sometimes every few weeks. This never used to happen in the past. Please, I really need help with this issue. If I back up my cookies beforehand, would restoring them after such a crash bring everything back to normal?