I would guess it is an anti virus problem. Try disabling email scanning in your anti virus and see how that works out over a day or so. Then try it enabled again. Sometime these anti virus issues just appear and disappear, they don't like an individual mail or something

Jeep1926 said

When I delete a message it does delete the message from my server, thus every time I download for new messages I get the new and all the old messages. After a couple of days the download will take up 3 or 4 minutes because of the number of messages and finaly it will just time out. Then I go to my charter account and manually delete each message. Charter says they do not support Thunderbird but it isn't a server problem

Thank you. This is the problem. Now I have to figure out how to get around the problem as I want anti virus protection. I just changed to Pandora from Norton.

The cause is simple. In this case Norton is chopping off the connection early... The last bit of information in the download is the where we are up to stuff. A solution I do not have, you would need to talk to someone at Symantec about it, but if you do get one, please post it here for the benefit of the next person with such an issue.

I have said this perhaps a thousand times. Anti virus protection on Thunderbird email is really something of over kill. Thunderbird does not allow any scripting in the email, so simply opening it can not infect your computer, even if it does infect your friends who use email that allows scripting. There is a very slight chance of infection from remote images, but your anti virus should be just as effective against them as it is against images in web pages and scanning the mail will not make any difference at all as images a fetched to display the image, not to receive the email.

The principal risk is attachments Thunderbird stores attachments as text (mime encoded, but text), so the attachment does not actually exist as such until you select to open it. To open an attachment, Thunderbird first converts the text to the original file type in memory. If it contains a risk your anti virus that is scanning memory should pick it up.

If it does not get a scan from the anti virus, or even if it does. The newly assembled file is them written to disk in your temp folder. Every anti virus I know of with a real time protection type module (including Norton) will scan new files in the temp folder for risk. Then Thunderbird passes the file name off to the operating system which goes off to get the application to open the file. This next bit is exactly the same as if someone gave you a file on a USB drive, you try and open it an your anti virus scans the file before you can.

What I am trying to say is that an attachment is scanned, usually multiple times before it is opened, even with anti virus scanning of mail turned off, so you are not really exposing yourself or your machine.

I have asked anti virus vendors why they scan e-mail, the most convincing argument they can mount is "another line of defense"

Hmmmm very interesting. I was having the same problem. I would delete messages in Thunderbird only to find them still on the server.

I just changed Anti-virus (from Norton to AVG) so i will try turning it off to see what happens. Thanks for sharing, it really helped!

NOTE-TWC insists that the problem is with my email client and since they don't support Thunderbird I am on my own. It would seem that someone there (Time Warner Cable) would know about the anti virus issue but they wouldn't even try to help me.