For some reason, I have a problem with Sent folder when I try to use Thunderbird. I can send messages but no copy is put in Sent folder and I can't figure it out. No problem tho, I am now using Mailbird (free for 2 mail accounts, paid for more than 2) and I really like the GUI and features of it. Thunderbird looks dated compared to Mailbird. The only feature missing in Mailbird is a built-in spam filter, but Mailwasher takes care of that for now. Shortly Mailbird will have one, tho, as I understand it.