1. Create a profile backup. 2. Create in thunderbird a new account with the same e-mail and server settings as deleted. 3. A new directory for the account with the next suffix will be created in the profile. For example, if your old email account directory was named pop.aol.com, pop-aol-1.com will be created 4. Go to Tools -> Account settings -> Server settings -> Local directory -> Browse to set the previous directory for this account and restart Thunderbird. 5. Check if e-mails are back.

Excellent, thanks for this. I got my old account back with all of the sub-folders and most of some of the old emails I had. Some of the older emails in my inbox are gone but at least I got back some of it. Thank you tremendously.