Unread messages showing as read in Mac Mail

[wyleyp]

Hello, I just purchased a new 15-inch MacBook Pro and had all the data from my previous MacBook Pro transferred onto the new machine. The OS on the new computer is Sierra10.12.2. I've noticed that new messages arriving in Mac Mail are showing up as though they have already been read. I'm very eager to get this fixed so that I can know at a glance what the unread messages are. (I've already tried deleting and re-adding the email account but the problem remains. I've also ensured that, under "Mail - Preferences - General", the "Dock unread count" and "New message notifications" boxes both say "All mailboxes." And, finally, under "Preferences - Notifications", I've ensured that "Badge app icon" is checked.) Thanks in advance.