I have to start off with the fact that i had a lot of open (but unloaded) tabs, like several thousands (don't judge or ask), this (as expected) has cause Firefox to slow down pretty bad, i also turned off that MultiProcess windows feature because one of my favorite plugins didn't work with it on, so that didn't help. The slowdown got so bad that i kinda avoided using Firefox, it took literally 5 minutes for it to load completely, although other than the titles and favicons of the tabs i really don't know what needed to be loaded for so long, this also took up like 4GB of ram, even though the sessionstore file is 23MB, seems like more work could be done on that. Anyway i clicked the wrong browser tab today and it opened Firefox instead, which opened just fine and fast because it was asking me to restore the previous session (last time i used it i think i had a power loss), so i clicked on restore and it seemed to get to work as usual and the last open tab loaded, but nothing responded and when i clicked on anything it said Not Responding in the top bar, this isn't anything unusual to me, usually it recovers in 30 seconds or less, but this time it didn't, so i was forced to close it. I opened Firefox again, hoping this time it would load properly, but i got the "firefox is upgrading" message and after opening the Restore session dialog was there again, but it was empty and the Restore button was grayed out, which makes no sense really. So i searched online for any solutions, found some about the Sessionstore JS files, made a backup of the Sessionstore-backup folder and the sessionstore.js file, but these solutions never say what exactly you're supposed to do, they only go as far as to tell you where the session files are, nothing more, like how is that any help? Anyway i copied the 'previous.js' file from the backup folder and replaced 'sessionstore.js' file with it, all the while FF was open, so i closed it and reopened it to see if it worked, but nothing changed. Any suggestions ? One of the support topics (https://support.mozilla.org/en-US/questions/1179413) had a link to Jefferson Scher's site which took any of your session files and extracted all the links from them and i used that and i got a massive list of all the tabs i had and their URLs, so with a few weeks work i could add all those back by hand. That same topic talked about recent changes to how the sessions were being stored (moved from .js files to compressed .jsonlz4 files), seems this is NOT backwards compatible and therefor automatic upgrades should be DISABLED. This is also probably why the 'Restore Previous Session' button is grayed out in the History "tab". Is there any way to use my 'previous.js' file to restore my session ? cuz it's intact, all my tabs are there, Firefox just won't use them, do i need to make a sessionstore.jsonlz4 file ? i don't seem to have on at the moment, also how do i compress a .js file to a .jsonlz4 file ? (The 'Automatically add' troubleshooting information button when making a new post seems to be broken, took me to a page not found page, used the manual way.) I will be monitoring this daily, so feel free to answer with anything relevant.