Do you have the profile you exported from old computer? I do not know Mac, but use the file management software to view the Mail\Local Folders folder of that extract. The local folders should be there. If not, they were not captured when the transfer was made. Local folders can not be subscribed because they are not part of an account.

Hi David. Thanks for the quick reply. I'm not sure if the old profile transferred. I did have to download a new version of Thunderbird and I set up my account that way. Unfortunately, I don't see the many emails that I had stored in multiple folders. Perhaps they are on my Hard drive somewhere? I just did a search Mail\Local Folders on my MacBook Air hard drive, with no results.

Not sure what to try next. Thanks again. Taylor

The files would have been on whatever you copied from the old PC. I was hoping you might have it on a USB stick. The current machine would not have it.

I thought that those files (folders with old emails) would have existed on the Mozilla server and I would be able to subscribe to them once I set up my new Thunderbird account on the new mac.

Guess I was wrong...

To any Mac users (not sure about PC's)... I suggest doing a direct computer to computer or external HD transfer when replacing computers and not using the Cloud transfer. Cloud transfer works good on phones and tablets, but I've just learned the hard way that it's not a compete transfer for a computer.

Thanks again.