Memory?

As Defraggler is running the free space indicator shows that my memory is slowly decreasing (start = 3.8 GB) (middle = 3.5 GB)

(End = ? (not done yet)) I don't know if it's a bug or just the sheer amount of defragmenting I'm doing (About 75 GB of fragmented files, somewhere around 72,000 fragments and around 7,300 files) (I haven't defragmented in a loooooooooong time :lol: ) or maybe some other problem.