From what I can read, I'm not the first to have this issue.

Currently attempting to install Colonization, though promptly being told that I do not have enough disk space. I have not partitioned my drive, I'm running only one hard drive, currently sitting at 191 GB free space - or upwards of 9.000 times the amount of space this game requires.

Installing with the backup installer now, but this might be something someone would want to look into...

lol, i do remember how some time ago certain games expected at least 50 gb of free space but this... this is really the other side of that live ;)

Never had that issue with a GOG game.

I have had old DOS games do that with the original physical editions I owned. When the game checks for free hard drive space they just error out on larger hard drives and come back saying not enough space.