How can I keep my e mail in the in box forever?

My messages are being deleted automatically after a certain amount of time.

How can I keep my e mail in the in box forever?
This is not the way the in box is set up, it is a glitch. The email is supposed to stay in the in box until you move it or delete. If you are using the New Mail could be the reason. Many have gone back to the classic mail for now until Yahoo gets the bugs out. If you want to stay in the new mail, the best thing to do is create folders and immediately put the email into it.