What happen to your passwords? What about the rest of your profile? Settings, bookmarks, history, passwords . . . . Firefox 80+ has a logins-backup.json file in the profile folder that can be used in case of issues with logins.json or to undo an accidental delete of a login, so you can check if you can find this file in the profile folder or in a backup and replace the current logins.json. Make sure to keep a backup copy of all involved files (logins.json and key4.db and logins-backup.json) You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page. Help -> More Troubleshooting Information -> Profile Folder/Directory: '''Windows: ''' Show/Open Folder; '''Linux: ''' Open Directory; '''Mac: ''' Show in Finder https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data If you use a Primary Password then you can prevent losing passwords by canceling the PP prompt. You need to logout beforehand by canceling a PP prompt, e.g. by clicking the eye icon in Lockwise (about:logins). Also see; https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update