Password for what? Does it ask for a 'Primary Password' ? This would be something you previously set up in Thunderbird to stop prying eyes seeing your stored passwords. You may have done this if you share your computer with other people AND also let other people have access to your computer User Account. The 'Primary Password' is not your mail account and should always be unique. Are you being asked for a mail account password? Are you trying to set up a new mail account or do you already have a mail account for an email address which has worked ok but is suddenly it's asking for a password ? In Thunderbird, passwords are stored in the following location: * Settings > Privacy & Security * Scroll down to Passwords section * Click on 'Saved PAsswords' * Do you see some accounts listed? * If yes, click on 'Show Passwords'. At this point you may get asked for a 'Windows security' password. When you start up computer, you logon to user account using a password - that is the password you need to enter. If you set up 'Primary Password' then it will prompt for that password. This should show you your current stored passwords. At this point you need to see if those passwords are up to date and useable. Using a browser eg: Firefox, logon to your webmail account to access the server view of emails using that stored password and email address. If you get access then you know the stored password is good. If you cannot get access to webmail account because password is not accepted, there should be a 'forgotten password' link which you need to use. Follow the instructions to allow you to get access to the webmail account where you can then reset the password for the account. Then in Thunderbird in the Passwords section - as mentioned above... * Right click on each relevant line (incoming and smtp) and select 'Edit Password' * Completely clear all the contents and then carefully type the correct password. * Then clickon 'Close' * Restart Thunderbird. If you use gmail or yahoo and use Authentication Method : Oauth - please let me know as you may need additional instructions.