As a first step, could you back up these 3 files from your profile folder to a location that Firefox won't modify (such as a new folder under Documents): * logins.json * logins-backup.json * key4.db And can you explain what happened with your Firefox? For example, was it uninstalled completely, so that all the data folders were deleted? Or did it have a startup problem and had to create a new profile? If you're not sure, try: [[Recover user data missing after Firefox update]].