Steam was great and then this roadblock happened.

[A Black Falcon]

I have 600GB of HDD space, in two 300GB drives, but I broke it up into four 140-160GB partitions, and I download and install a lot of stuff, so I'm now at 202GB free... 37GB on C, 18GB on D, 21GB on E, and 126GB on F. I'll fill it up sooner or later... Steam is on C, so it's got plenty of room to grow (I mostly don't put stuff on C beyond what's already there), but even so it's a sign of horrible design. I was shocked when I found that I couldn't set folders for Steam to install stuff to...