Today, I am getting organized want to make a sweeping change of all my email passwords for better security. But I couldn’t figure out how to change the passwords of my saved email accounts in Thunderbird. It isn’t the same situation as Outlook Express.
Here is the solution:
In Thunderbird, choose Tools>Options>Advanced. Click the button for "Manage Stored Passwords". You can make a full change by Removing All saved passwords, or just click and remove specific ones.
The next time mail is checked, an Alert box appears telling you that the password didn’t succeed. Click OK and a new window appears with the option to type in the new password.