Basecamp doesn't take up much space, it's the maps and Birdseye that does, .....
This is still an issue. I don't want other stuff on my C drive, and Garmin "presumes" I want it there. As a result, I don't use Garmin Express. In fact, maybe just leave the whole Garmin eco-system for something that doesn't hog up my C:\ drive with 475MB of program where I don't want it.
I just loaded Mapsource on my new Win10 laptop and it gave me the option of installing to the D: drive, no hesitation. What is up with Basecamp? Obviously the issue isn't the lack of installation program technology to give you the option. It is a real issue on smaller SSD drives. It can't take over six years to make such a small change. Very disappointing! I'm stuck with Mapsource.
As I posted above BC takes up so little space it's not an issue, your database (which can grow quite large) can be anywhere you want it.