I've tried the solution from this closed thread and it doesn't help. I'm on Debian based Linux using Firefox version 103.0 https://support.mozilla.org/en-US/questions/1349553 from about:config, every sessionstore has been disabled and sessionstore.max_resumed_crashes set to 0 If I close my firefox using 'x' or shut down computer before closing firefox directl, firefox restores the previous session. From a thread on support site that I can't find anymore, I read that the fault was that, firefox was reverting to default settings before closing when using 'x' instead of File -> Exit. I can't believe such a massive hole still isn't fixed. For me, the worst that can happen is someone will see a site that I find embarrassing on restarting. As stated in the other thread, if you're a journalist or someone else, in certain countries, this can become a life of death situation. Along with other shenanigans Firefox has been pulling, this kind of drives home the point that Firefox isn't the browser anymore if privacy and security is your main concern.