Deleting an account Thunderbird

This is an often asked question in Thunderbird support forums, and one that whilst easy to accomplish, is fraught with unexpected consequences.

Why you should be very careful in deleting accounts.

Thunderbird links messages to IMAP accounts.  If you delete an account, the messages associated with that account will simply vanish.  It may be possible to recover these messages, but it is certainly not something one would elect to do through choice. So the short of it is that if you have messages you want to keep, you don't really want to delete the account.  You might want to disable the account from checking mail, you might also want to remove the outgoing server from Thunderbird, but you don't want to delete the account.

Why you might think your need to delete an account

It is not working, or has stopped working. 
This is not Outlook Express where the answer to all problems is delete and recreate, or uninstall and reinstall.  Neither approach is likely to fix the vast majority of problems, but is highly likely to loose your mail in the process.  If you are having problems with an account that does not work, post your settings, there are shown in Trouble shooting on the help menu at the Thunderbird support site with a clear statement including the actual error messages you are receiving.

You have closed the account with the provider
As mentioned earlier Thunderbird will more than likely delete you mail along with the account, so you need to keep the account in Thunderbird, even if you exclude it from mail checking.

Disable the account from checking mails, by Going to Tools > Account settings > server settings and turning of the Check for new messages on startup and Check for new messages ever XX minutes. then click the advanced button and uncheck the include this server when checking mail if it is available.