Ever since I have updated from 4.8.x to 5.x.x - (pro version) a couple of weeks ago - I have noticed that sometimes thunderbird re-downloads previously downloaded e-mails. While I prefer to leave copies of pending / important e-mails on the mail server, I have never had this problem earlier.
I was using TB 2.x and then updated to 3.x, but the problem persists. I have deleted the inbox.msf file, but nothing has worked. The thing is that all the e-mails on the server are not re-downloaded, but only some. I do not think TB is the problem, but probably avast is, since only after updating to v5 have I ever had such an issue.
If somebody could look into this / help I would be quite grateful. The duplication is becoming quite irritating. TIA