I have a Zumo 550 in which i installed the latest map: City Navigator North America NT 2016.20.
I next installed Basecamp. When I open the App there’s a Notification  that reads:  “No Detailed Maps Found.  You can enhance your user experience by plugging in a device with preinstalled maps or by purchasing maps online.”  The Maps menu only displays the Global Map.  
When I plug in the Zumo 550 it displays the City Navigator map that was installed.  
My question is how do I install the map on my Macbook Pro and use it without having the Zumo plugged in?  This is what I tried but to no avail.
When I open MapManager it says “No compatible maps were detected.” I did File/Install Map and browsed to Library/Garmin/Maps or Library/Garmin/Express/Maps and selected the City Navigator…gmap it goes through the installation but does not display the map.  And Basecamp doesn’t see it as well. It’s probably a simply thing that I’m missing.
Any help will be greatly appreciated.
Kent