I have a Nuvi 2599LMT-D and I have installed the new City Navigator 2019.30 on it and also on PC using Garmin Express, but now when I open Basecamp the map is not there.
I have done it with the same result. I think the files are on my computer, because I see them in my Maps folder (c:\Garmin\City Navigator Europe NTU 2019.30.gmap) and with a size of 5.22GB, but in Basecamp I see all my maps except this one.
I have uninstalled the map (and surprisingly it has remove also Basecamp!!), then I have installed the map again using Garmin Express, but now in the folder by default (the one you mentioned c:\ProgramData\Garmin\Maps). When it finished I had Basecamp again and now I can see the map there. So it works.
The version of Basecamp was old, so I couldn't see my newest tracks. I have updated Basecamp to the last version 4.7.0, and that's all. Now I have all of my tracks and also my City Navigator map.
