Hi Sadean. You bring up a good point about possibly loosing emails. From everything I've read on the internet, the settings for POP should be "pop.mail.yahoo.com" and port 995. Everything else stays the same as in my above post. I have not personally tried this, but as long as you enter it as POP and not IMAP you have nothing to lose by trying it. Please report back, it may help someone else.
Nosed around, and apparently I needed a one-time password at Yahoo to use when signing on to Thunderbird for the first time. Here are the instructions for that.
https://help.yahoo.com/kb/generate-third-party-passwords-sln15241.html
It worked for me :)
