Hello, this is an issue that's happened to me twice this week and it's really strange and I need help. Tried browsing the forums and googled everything that I could but it seems that noone has had the same issue? What happened was that I had a bunch of tabs open, then suddenly firefox starts getting super slow, it works but I can't add any new bookmarks, I can't save my bookmarks as either json or html and in general it refuses to make any change to the interface of the program itself. The speed and disc usage gets better once i close all but one tab. BUT. When I close the whole program and reopen it a while later, my history and bookmarks get reseted to the state week ago (Today is 4.2. and I've been using the firefox without closing it daily now but firefox history tells me that the last time I visited a website was on 30.1.) I've tried checking if I'm on the default program, or if I don't have the option for starting reseted checked, but it all seems okay. Now, when it happened a few days ago for the first time, I was livid, because I lost very valuable data and mainly about 50 new and important bookmarks (and since history got wiped too, I didn't even know what exact sites those were). What I did was save the bookmarks, both as json and html. Today it happened again. And the saves are GONE. I can't explain it. They are not in the trash bin, there's no history of them. Searching won't show anything. I tried scanning my PC with my ESET antivirus but it seems alright. I'm honestly freaking out. Any clue of what might be causing it? I would honestly hate to go through this again and again. I have the latest update to Firefox and I have WIN 8.1.