Have you tried compacting your In-box? Are you getting any error messages?

Confirm that you have the correct server settings.

From the Menu Bar select Tools-Account Settings-Server Settings

No menu bar? press the alt key.

mail.comcast.net Port 995 SSL/TLS normal password

No error message and I have compacted. I keep getting the same 1 email over and over. It says I have received 1 of 28, but no more come in!! It is like it is stuck in a cycle. I can go to my e-mail through another server, but nothing but the one comes in through Mozilla Thunderbird.

Close Thunderbird. Log onto the web mail page of your ISP and delete the oldest message in the inbox that has not yet been downloaded to Thunderbird. (Or move it to a server folder other than the inbox.) Launch Thunderbird and try again to "Get Mail".

Sometimes a message with a malformed header can block Thunderbird from properly reading and downloading it from the server and that can prevent the download of the other messages in the server inbox.

I did as you said, and now all of the latest e-mails have downloaded. Thank you very much for your help. Tott

I have no messages on the server and this freeze up crap is happening to me. Says it can't write to disk so it doesn't load mail to the computer but it does delete it from the server. I am uninstalling this crap.