I just cleared all the files in Previous Versions and it cleared 52GB of my disk space! I was wondering why I used so much disk space in just 1.5 weeks of computer usage! So it is Previous Versions. (Some people refer to it as Shadow Copies.)
It’s useful if you want to restore a particular file that you have modified but you’ve got to clear it to sometimes if you want your disk space back.
[Previous Versions is a feature found in Windows Vista Business and Ultimate, I don’t think it is in Home Premium or Home Basic.]