See [[Password Manager - Remember, delete and change passwords in Thunderbird|password support article]]

Do you mean you have recently accessed the webmail account and modified your passwords and therefore want to edit the stored passwords in Thunderbird ? If yes: The password support article will help but it's not up to date and is missing the latest changes. * Settings > Privacy & Security * Scroll down to 'Passwords' section * Click on 'Saved Passwords' * Click on 'Show Passwords' At this point you may get asked for a password. This will be one of two options: '''1. '''If you have selected the checkbox 'Use a Primary Password' Then previously you must have set up a special 'primary password', You will be asked to enter that 'Primary Password' to get access to stored passwords. This is not a mail account password, it's something completely separate which you would have set up. If you really cannot remember that 'Primary Password' - then you have no option but to remove it entirely. This means all stored passwords for all your mail accounts will automatically be deleted. How to remove the 'Primary PAssword': * https://support.mozilla.org/en-US/kb/protect-your-thunderbird-passwords-primary-password#w_reset-your-primary-password-if-you-have-forgotten-it Then restart Thunderbird. The 'Primary Password' should now no longer exist. At the prompt, enter the new imap mail account password. Select the checkbox to 'Remember Password' and then click on 'Ok' '''2.''' IF you have NOT selected the checkbox 'Use a Primary Password': then you will see a 'Windows Security' small window and it wants the computer user account password...When you start up computer, the first thing it asks for is a password to get access to your User Account or Microsoft account - that is the password it wants.