Hi   !
You should be able to recover your passwords by using a Windows trick called "Previous versions".
See : https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data#w_finding-your-profile-without-opening-firefox

You'll need to navigate to your Firefox profile folder and right-click the profile folder itself to see an older version of it. Select "Restore previous versions" on the folder; find a folder dated before this happened and backup/copy the entire folder to another location.

You can also just copy the signons.sqlite and key3.db files. You MUST copy both these files together as they are connected to each other. key3.db does the encryption and signons.sqlite stores the passwords. It may be enough to just copy the old signons.sqlite file and drop it in the profile folder since the key3.db file might not have changed. You can experiment with that to see if that works.

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.

These can't get your data back, but will help in the future.

These add-ons can be a great help by backing up and restoring Firefox

https://addons.mozilla.org/en-US/firefox/addon/febe/ FEBE (Firefox Environment Backup Extension)

FEBE allows you to quickly and easily backup your Firefox extensions, history, passwords, and more. In fact, it goes beyond just backing up -- It will actually rebuild your saved files individually into installable .xpi files. It will also make backups of files that you choose.

https://addons.mozilla.org/en-US/firefox/addon/opie/ OPIE

Import/Export extension preferences

Happy112 said

Hi   !
You should be able to recover your passwords by using a Windows trick called "Previous versions". <snip>

To Happy112: Thanks so much for that answer. A link to this thread was posted on MozillaZine's Firefox Support forum and it helped another user recover his missing logins/passwords. See: http://forums.mozillazine.org/viewtopic.php?f=38&t=3031810 Posted 16 Jul 2017 by KasperskyITA (quote) Thank you very much for the information. I solved taking a version of a week ago of the key3.db and logins.json files.

_{Note that passwords are stored in the key3.db and logins.json files in current Firefox versions. Ref: https://support.mozilla.org/kb/profiles-where-firefox-stores-user-data#w_what-information-is-stored-in-my-profile aw}