Thunderbird does require a log in. Maybe you've set up a master password? That is required to be entered every session.

I can use it to log into Thunderbird but it will not save it.

You'll need to tell Thunderbird to remember the password. Pay attention when you do see the password prompt.

I get this error (#MBR1212) I can enter new password all is fine but when I tell it to save it just sits there and does nothing. When I go to get messages same error. When I check passwords still has old password. It's just not saving it.

Try adding @verizon.net to your username in Account Settings.

no help, at a loss. Can I go in and replace old password with new?

In recent versions of Thunderbird, yes, you can edit stored logins.

Open the password store, use the filter at the top to find the relevant account's logins. Set it to display the passwords. Right-click an entry for a pop-up menu that lets you edit, copy or delete login details.

Prior to this being introduced I would have advised you to simply delete the old login and its password and expect to be prompted when their absence is noticed.

Note that you'll have at least two entries per account; one for incoming and one for outgoing.

Zenos, Had opened the passwords but never even thought they were editable, Thanks