To tackle your second question first, and also partly to answer the first: yes there is a way to do it, but using IMAP rather than POP. IMAP is designed to synchronise your messages and folders across a number of devices -- so (for example) you could use a computer that gets Yahoo Mail in an internet browser, a phone that gets it in its own email client, and a PC that gets it in Thunderbird: you would see the same messages in the same folders in all three. If you want to go down that route, there are instructions here: https://support.mozilla.org/en-US/kb/switch-pop-imap-account If you do switch to IMAP then Thunderbird will pick up the messages in your 'sent' folder (your first question). If you don't want to switch, then the best way to get them is to move them ''on the server'' from 'sent' to 'inbox', download them to Thunderbird as 'new mail', then ''on Thunderbird'' to move them into a 'sent' folder -- but it's laborious!

Thanks very much. That helps