I've just completed a full partition copy. It took 20 hours for 470GB (don't know why, because CloneZilla does it in 4H, and I turned compression off, but whatever). Now I'm trying to do a differential backup of the same partition and the Wizard says the differential will be the SAME SIZE as the original partition copy? Why? I thought differentials are only supposed to only track changes? Attached are images of the folder properties showing the size of the full backup, and the Differential Backup dialog showing its estimated size to create the differential (which is pretty much the same size as the original full backup). I'm confused.