I usually have lots of tabs and windows open (often over 500 tabs). Firefox occasionally crashes, or needs to be shut down, after which I restore my windows and tabs using the Session Restore function ("well this is embarrassing..."). This system has worked well for me until a few days ago; I'm guessing that Firefox updated itself to version 42 and changed how it handles sessions. What now happens, is that Firefox, when restarted, not only gives me the option to restore the windows and tabs that were open when Firefox crashed - it's also, by default, set to open windows and tabs for sites that I've visited previously that day, but which I may have closed hours (or maybe days?) ago. So instead of opening maybe 30 windows, Firefox will ask me if I want to open 50 windows, 20 of which I have already closed by hand and which I'm not interested in. That means that every time I restart Firefox (which happens several times a day), I have to carefully check hundreds of sites to see if they were sites that I did in fact have open, or if they were sites I read yesterday and had already closed. Is there any way I can restore the session functionality of previous Firefox versions, when Firefox only restored the windows that I actually kept open when Firefox crashed or restarted?