I was hoping someone more expert would help you out. It depends on so much! If you were using POP then all the emails you see are right there on your computer already. If you were using IMAP you might have the whole message or you might only have headers and not the content. If you ever set up 'offline' settings you might have all the emails you previously opened somewhere in offline folders. So - if you are able to open and read all the messages you downloaded, they are on your computer with complete contents. That's good. You need to put them somewhere safe (very important) before considering removing or editing the account so it doesn't prompt for password any more. Make a safe copy of the Profile (look up Thunderbird Profile for where it is and how to make a copy/transfer/backup the profile). Then make a set of folders in Local Folders part of the Thunderbird. Copy batches of the emails from your Uni account to the Local Folders section - a few hundred at a time. Take it slow, check the emails copied over and you can read a few after each batch. When you have all that you want to keep in Local Folders, make another Profile backup copy. Then check once more and then delete the account - Account settings - Account actions - Remove account. That will also delete all the emails in the account's inbox and subfolders which is why you need to copy all to the Local Folders section first. Good luck!