Why don't Garmin release a version of Basecamp that actually works and has a version number > 4.7.0. At the moment, every time I use 4.6.2, BC wants to update itself to 4.7.0, which doesn't work correctly with IMG files.
This restore correct functioning of BC with copying of IMG map files to Garmin devices. I don't know if 4.7.0 breaks anything else that works in 4.6.2, but the procedure above restores the functionality that I use.