While Firefox is closed, try creating a copy of logins.json.corrupt and renaming it to logins.json in case Firefox actually can read it.

Otherwise, hmm.

Okay, interestingly enough, I've done an install of Ubuntu Studio now and all of my passwords are back (my Arch install was starting to act a little weird so I think something was wrong under the hood somewhere.)

It even saved my password for Mozilla Support despite me only saving that to my sync account after the other passwords had disappeared. I'm just glad sync is smart enough to not say "oh all your passwords are gone locally, I guess I'll delete them from the server too!"

Thanks!

That was very good work. Well done. Please flag your last post as Solved Problem so others will know.

In the event that the passwords information is lost, you should record all information in a separate text file somewhere else on your hard drive, or written down. You can easily copy and paste if you need to do so. If you are concerned about someone else looking at that file, you can compress it using a password.

Back up and restore information in Firefox profiles.{web link} I use an add-on that makes backups of my user profile, Just In Case. Unfortunately, it is not compatible with the current Firefox.

Every now and then, open the profile folder and create a copy of the current profile as is to another location on your hard drive. This way you will have a backup.

If you do this each day, you will not lose much data. This should be done with Firefox Closed.

Note: In case you need to restore from these backups, you may need to overwrite old or corrupted files.