Try if you can find available maps in "Tools" - "My Data" - "Map Sets" - "MapSource" or something like that i don't know the exact structure of device's menu (KNA-G620T).
ok i put it on the sd card, when i insert it in the kenwood how do i load it ? do i press a button or something ? because i cannot see the maps on the navigation
maps are on sd card plus in navigation unit but when i disconnect usb it says detailed maps were not found why