'Primary Password' is a specific setting. It used to called 'Master Password' because it was a used as a Master key to gain access to all stored passwords. More info here for anyone reading this who needs more information: * https://support.mozilla.org/en-US/kb/protect-your-thunderbird-passwords-primary-password#w_reset-your-primary-password-if-you-have-forgotten-it The 'Primary Password' prevents anyone who has access to your computer and your user account from opening Thunderbird and viewing your stored mail account passwords. That's all it does. This is not a default setting. It is something you chose to set up for your own reasons. For some reason you were prompted for the 'Primary Password' and you have forgotten it. It sounds like you followed the correct procedure to 'remove' your forgotten 'Primary Password' - I've added an image below for those who are unsure - but did you exit Thunderbird, wait a few moments for background processes to complete and then restart Thunderbird? If no then please do this now. After exiting and restarting Thunderbird Settings > Privacy & Security Scroll down to 'Passwords' section. The checkbox 'Use a Primary Password' should NOT be selected. However, because setting a primary password was designed to protect your saved passwords and you have removed it completely, it does mean all of your mail account passwords would have also been deleted in order to protect them - why - because anyone can remove a primary password, so Thunderbird must act to protect mail account passwords. That means after restarting Thunderbird, your mail accounts will attempt to access the server to get mail, but as no password for the mail account is stored - you will be prompted for the password for the mail account. * Enter correct password for mail account email address at the prompt * Select the checkbox to 'Remember Password' * Then click on OK. The password is usually the same password you use to access your webmail account directly via a browser. Some servers now require an app specific password. But without knowing anything about the servers you are connecting to, I cannot advise whether you need an app specific password. I would need to know the following: In Thunderbird * Help > Troubleshooting Information * Scroll down to 'Mail and News Accounts' * Copy all the data and paste it into this forum question OR post an image of it.