Are you talking about the primary password? https://support.mozilla.org/en-US/kb/protect-your-thunderbird-passwords-primary-password The article includes information on how to reset that. Are you talking about your account passwords? Those are stored, but not set by Thunderbird. See https://support.mozilla.org/en-US/kb/password-manager-remember-delete-change-tb If you have issues with your account password, I suggest you contact your mail provider. If Thunderbird has suddenly started asking for a password after working without a request for a long time, the problem is probably your antivirus program and not Thunderbird at all. The following diagnostic process will help in identify that; * Does Thunderbird work as expected in [[Troubleshoot Mode Thunderbird|Thunderbird troubleshooting mode]]? * Does Thunderbird work as expected with your OS started in '''[http://en.wikipedia.org/wiki/Safe_mode safe mode with Networking]'''. Instructions for each operating system: [https://support.microsoft.com/en-us/windows/start-your-pc-in-safe-mode-in-windows-92c27cff-db89-8644-1ce4-b3e5e56fe234 Windows 10/11], [https://support.microsoft.com/en-us/windows/windows-startup-settings-including-safe-mode-7f31dcea-6427-0ba0-ec1b-729a56321cd3 Windows 8], [https://support.microsoft.com/en-us/windows/advanced-startup-options-including-safe-mode-b90e7808-80b5-a291-d4b8-1a1af602b617#start-computer-safe-mode=windows-7 Windows 7], [http://support.apple.com/kb/ht1564 OSX]