Any specific reason for using Firefox 72.0.2 and not the current release ? *https://support.mozilla.org/en-US/kb/update-firefox-latest-release You would need a backup of logins.json (encrypted usernames and passwords) and key4.db (encryption key) to recover lost login data. *https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile You can check in Windows Explorer if there is a previous version of the <b>logins.json and key4.db</b> file available. *right-click: Properties -> Previous Versions *https://support.microsoft.com/en-us/help/17119/windows-7-recover-lost-delete-files