Does this happen in all folders? I'm puzzling over your "Copies to Self" folder, which appears to have the "Sent" icon. I wouldn't call sent items "copies to self"; I'd use that description for messages where I'd put myself as a Cc: or Bcc: recipient. Some services such as Gmail, don't return self-addressed Cc: copies to you, arguing that since they have already put a message into Sent, you don't need to waste time, energy, bandwidth etc actually sending that message; you already have a copy. Anyhow, I'm looking for reasons why a Sent folder might not be populated, or why it might not appear to be a valid folder in Thunderbird.