That is the % of used space taken by that particular folder and not % of total space on drive...
Sorry for dragging up this old thread but I've been having the same problem. Did you end up finding a solution kush1543?
The free space on my c drive keeps going down even though I've deleted several gb worth of software and files. This has been going on for a couple of months. According to windows I only have 255mb free space (2 weeks ago it was 4gb and I haven't installed anything new since then). Yet, according to TuneUp Disk space explorer, I should have about 60gb of free space.
Right now, besides Windows, the only things left on my c drive are a few basic softwares like Photoshop and one 6gb game.
I've checked for viruses, spyware and malware. Also, Hibernation is disabled.
Any ideas? Any help would be greatly appreciated.