Hello,

What security software do you have?

There have been reports that AVG/Avast is causing issues with passwords disappearing. You can check the profile folder to see if there are logins.json.corrupt files present. If you find such a file then try to rename logins.json.corrupt to logins.json.

• keep a backup copy of all logins.json files

• You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:

• Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder

• http://kb.mozillazine.org/Profile_folder_-_Firefox

Hope it helps. Thank You !!

Hello, What security software do you have? There have been reports that AVG/Avast is causing issues with passwords disappearing. You can check the profile folder to see if there are logins.json.corrupt files present. If you find such a file then try to rename logins.json.corrupt to logins.json.

• keep a backup copy of all logins.json files

• You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:

• Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder

• http://kb.mozillazine.org/Profile_folder_-_Firefox

Hope it helps. Thank You !!

Renaming didn't solve the problem, since it's corrupted with a size of 0 bytes. So all the logins and passwords are totally lost.

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.

I guess that's what I have to do from now.

Are there any logins present in logins.json or do you have a logins.json.corrupt ?

Note that Sync isn't meant to be used as a backup device.

You can install the About Sync extension in Firefox 72 and newer on desktop to check what data is stored on the Sync server via the about:sync page provided by this extension.

• About Sync https://addons.mozilla.org/firefox/addon/about-sync/

You may have to close and restart Firefox to access the about:sync page added by this extension (see the about:about page for available about pages).