It would seem that you have set up Thunderbird to use a 'Primary Password'. The 'Primary Password', also previously known as 'Master Password' is used by people who share a computer User Account. So for anyone who allows people to access their User Account, which means they can access all the documents, setting a 'Primary Password' might be very useful. It's purpose is to hide access to the stored mail account passwords. If only you use your computer or only you know the pasword to access the computer 'User Account' it is not really of much benefit. If you have forgotten the 'Primary Password' you can completely clear it. However, this also means all your stored mail account paswords will also be deleted as a security protection. After all, it would not be much use if anyone could simply clear it and read your mail account passwords. This is the Help Article on how to remove it: * https://support.mozilla.org/en-US/kb/protect-your-thunderbird-passwords-primary-password#w_resetting-your-primary-password-if-you-have-forgotten-it Please note you must copy and paste the entire '''openDialog''' line. I've included it below although it is available at the link above in Help Article. * '''openDialog("chrome://pippki/content/resetpassword.xhtml")''' See image below as guide. When you have done this, you need to restart Thunderbird - this is important. It will then prompt for passwords - this time it is asking for the 'mail account' passwords. Enter the correct password for the account/email address. select the checkbox to let password manager remember the password and then click on OK. If you have more than one mail account then you be asked to input password for each account.

If you need to enlarge the image which I included in previous comment: Locate this question in forum and click on the thumbnail image and it will appear much larger.