My PC crashed probably due to some hardware issues. After rebooting, FIrefox Sync is disconnected, but when I reconnect it, all my logins and passwords are gone. I have searched the profile directory, there is a logins.json.corrupt file from the time of the crash, but empty. The new logins.json file is empty too. There is only one profile directory (as expected). Any ideas anyone if I could restore the logins file to the state before the crash, or how I could prevent this from happening next time? Thanks.