One unread message in smart mail box
Can't get rid of it the one unread message which doesn't show in the smart mailbox or inbox general.
Tried marking all messages as read, deleting and remaking, rebuilding mailbox, still the ghost email lingers.
Designer OCD is annoyed.
10.13.6
iMac (Retina 5K, 27-inch, 2017), macOS Sierra (10.12.6)