Base Camp sees 2014.20 but

Basecamp recognizes .img files, MapSource cannot.

In order for Mapsource to recognize your 2014.20 map you need to download it again, and select download to "computer only". I suggest you use Mapudater to do it.

Once the map files are downloaded to your computer they will be seen by Mapsource. If you wish to delete other map versions that Mapsource sees you'll find the files in:

C:/programdata/garmin/maps

The files will be named City Navigator North America NT (version number).gmap

With Windows 7 or 8, at least, you may need to have hidden system files and folders viewable in order to see the Programdata folder.

I have the maps installed on my computer, actually even before I made the original posting.

This is the location where the 2014.20 is installed.
BTW, I prefer to have installed programs on my second partition to have faster access to Windows or other necessary operating files.

E:\ProgramData\Garmin\Maps\City Navigator North America NT 2014.20.gmap

How do I get MapSource to see it?

Hmm, I'm not sure. Did you use GarminMapUpdater to put the map on the computer? When I've had GarminMapUpdater install the map to computer (mine is a PC) and device (both accepting the standard location and also for a 2nd drive partition as you've done), Mapsource sees the map.

So for me, if you installed the map update to your computer with GarminMapUpdater, I'm surprised that Mapsource doesn't see it. My Mapsource always sees the new map installed this way, both the current 2014.20 map and for several years of previous quarterly map updates.

If you installed the map update to your computer by some other technique, tell us what you used or did.

One last thought. GarminMapUpdater has two similar-sounding options when installing maps: 1) leave installation files on computer; and 2) Install map to device and computer (or Install to Computer). When I say it works for me with GarminMapUpdater, I'm referring to #2, above. Is this what you've done?

When deleting previous map versions no longer wanted or needed--or for extra hard drive space--I use the Windows "uninstall" or RevoUninstaller so that other files or registry settings are also deleted.

I fired up BaseCamp and it asked me if I want to update to the newest version. I agreed and afterwards BaseCamp can not see the map either.
Both MapSource and BaseCamp only see the basic Garmin map.

I reinstalled the maps using GarminMapUpdater 3.2.2 and chose to install to the computer and leave the installation files.

The second install installed to my original location on my 2nd partition without me chosing where to install.

I am going to try a third download, but this time let it chose on which partition to install. Maybe that is the cause of no recognition.

I too use Revo Uninstaller Pro and will remove the maps on my computer before another download.

Will report back after this 3rd download.

Removed the former 2014.20 install on my 2nd partition with Revo Uninstaller.

Then using Garmin Map Installer 3.2.2 reinstalled it to the default location on my C:\ drive and both BaseCamp and MapSource found it immediately.

BTW, this time the complete install took less than 5 minutes.

Thx