Don has been having trouble getting his email through Windows Live Mail. Some of it shows up on his Galaxy S4, but not all of it. He's learned that POP3 won't give him email on both devices. Leo says that's true, and the problem could be how Don added his account to his Galaxy S4. Don says it's a Gmail account, though. Leo says Gmail and Live mail are two different services and that explains why Don isn't getting all his email. He's only getting his Gmail.
Leo recommends that Don set up his Windows Live Mail client to use IMAP, not POP3. POP3 deletes the email from the server. IMAP will leave the email on the server where his phone can get it. If that doesn't work, then he can try having Gmail retrieve his Windows Live Mail and then work from just his Gmail account.