This is normal but the message was disabled. What I find are folk will use a registry cleaner or tune up software and it turns off the setting that hides that message.
As this is the recovery drive, it's not for you to use.
Widely discussed so I won't duplicate all that has been written. Ignore it or turn off the low space warning.
BEWARE THOSE THAT WANT TO HELP YOU FREE UP SPACE ON D:. That could break the restore feature.
I purchased this computer brand new but when I set it up it shows only 2GB Free on drive D (2GB free out of 17 Gb-- "IS this normal for a new computer?" I have never seen this low a disc space on previous new computers . But this is my first new HP desktop . (my concern is drive D is the Recovery drive .ANY ANSWERS Appreciated