The thing is all my received emails are perfectly visible & decoded on the Yahoo website but some are not in the Windows Mail client on my laptop.
However, when sending that same email from the Yahoo website to youself at that same address it then appears fully visible & decoded in the Windows Mail client on my laptop. It sits in the same inbox as the original email sent earlier from the original sender which still won't appear properly.
It gets tedious having to keep on logging into the Yahoo website and sending emails to yourself to get them to appear properly on your laptop/ computer...