Repeated multiple copies of individual message

I am getting repeated multiple copies of an individual message using Thunderbird 3.0.5. I have deleted the message and compacted the folders numerous times, but it shows up later each time. Often several copies with the same time date stamp appear.
I have gone to my ISP's mail server and deleted all copies there also. It has not reappeared there.

 

It happens when the header file is corrupted. In case you don't know, the e-mails of a given account are in files like: Inbox, Sent, etc. and there are equivalent Inbox.msf, Sent.msf, etc files. These are found in the Profile|Mail|account folder in Windows Explorer, if you use a PC. The way to eliminate the problem used to be to close your mail program, open Windows Explorer, and locate the files in the above path. If it is only incoming mail, delete the Inbox.msf file. Then close Windows Explorer, open Thunderbird, and things should go back to normal. As farr as I know your method does not have any permanent effect.
Having said that, I don't understand your last sentence. By

do you mean that you went to webmail of your ISP, and found duplication or more, and that problem went away after deleting the excess mail, or what did you do?

 

I was simply stating that I deleted the original message from the webmail server to be sure it wasn't a problem from that end. It's a bit late here and so I won't try your info until sometime tommorrow.