Did you read this support article? *https://support.mozilla.org/de/kb/reset-your-primary-password-if-youve-forgotten-it If the chrome URL (chrome://pippki/content/resetpassword.xhtml) isn't working then delete logins.json and key4.db and key3.db in the Firefox profile folder. You lose all passwords stored in the Password Manager if you reset the Primary Password by using the chrome URL or delete the logins.json and key4.db files. You may want to keep a backup copy of logins.json and key4.db in case you remember the PP or if you want to check for what websites you have a login stored (the URL is not encrypted in logins.json). You can use the button in "Help -> More Troubleshooting Information" (about:support) to go to the current Firefox profile folder or use the <b>about:profiles</b> page (Root directory). *Help -> More Troubleshooting Information -> Profile Folder/Directory:<br>Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder *https://support.mozilla.org/de/kb/profiles-where-firefox-stores-user-data