I'm trying to reinstall email account on Mac Mail, but it says the account already exists
I've had to remove my main email account from Mac Mail because a glitch stopped it receiving mail. I'm now trying to reinstall that account but, after entering the details I get a message saying that the account already exists. Although I removed the account itself (it no longer shows up in the Accounts pane) I don't think I disconnected it from other apps such as 'Notes' or 'Contacts'. I now can't find a way to totally remove the account from the system, so I can do a clean re-install.
Any thoughts would be gratefully received.