Hi Ed, in basecamp something called 'Map Product Manager' lists 3 maps under the 'map product information' tab. The first map listed is 'City Navigator North America NT 2015.4' version '18.40' status is 'locked' location is c;\program data\garmin\maps .... etc. There is an option to Unlock online in a button on the right of that page. When I click that button it takes me to 'Garmin unlock maps' internet page where I click a 'find device' button. Even though my zumo is connected and showing the computer interface icon on the screen it is not detected and nothing happens, just says 'looking for connected devices' forever. A Zumoforums post suggested that with my versions I should be able to to simply connect my Zumo and open basecamp and discovery and map transfer would be automatic but I get no love there. Have now been at this all weekend (a couple of 3+ hour long downloads allowed me to get out of the house). I can see how many users would give up in frustration.
EUREKA! Was able to unlock from 'mygarmin' so I should be able to move forward without impediment.
Thanks for putting the tutorial together Ed.