It's slowly dawning on me that this might be an unfixable problem, but I'll ask anyway. When I updated my Macbook this morning, Firefox updated as well, and when I opened it, all my bookmarks, history, passwords, and extensions were missing. My Mozilla account was signed out, so I signed in, but since my password was only saved on Firefox, I had to reset it... I think this may have deleted my data permanently. Weirdly, a similar thing happened to me with a recent previous update where all my bookmarks vanished. I tried to follow the guide to restore bookmarks, which didn't work, but when I quit and restarted Firefox they came back anyway so I didn't think too much about it. It's definitely my fault for panicking and resetting my account password without reading the consequences too carefully, but I don't understand why these updates sign you out of the browser in the first place. I'm not the most tech savvy person in the world and it wasn't like they were warning before the update to make sure all my data was backed up... they just sprung it on me at 7 on a Saturday morning. Sorry for complaining. If anybody has any idea how to fix this, I'll be eternally grateful.