IMHO, what happened is that 'Carlos Danger' at one point in his marriage used that computer.
And Huma simply took Anthony's word that he deleted all her email accounts and connections to the server(s), etc.. She never thought of it again.
In the meantime, he was getting all the 'protection' on his life he would ever need....on a daily basis.
650K emails probably goes back prior to her years at State.
They got her....they got Huma....they got Rice...they got Jarrett....they got Obama!!
THAT'S why Comey announced when he did, 1-1/2 weeks out. It's why they rushed to get the search warrant for the computer.