How do I delete an email account from Thunderbird?
Before you remove the account from Thunderbird, move any emails for that account that you want to keep into a folder under Local Folders. When you remove an account any messages associated with that account that are not moved to local folders will disappear with the account.
From the menu bar select Tools-Account Settings Select the account that you want to remove At the bottom of the account list is Account Actions-Remove Account
No menu bar with Tools? Press the alt key.