During Disc Defragmentation, my hard disc seemed to lose space

Question

I started out with 57.1GB and once i started defragmenting, the hard drive went down progressively to 56.7GB. And continues to go lower while defragmenting. Is this normal?

Answer 1

is that free space, or space consumed?

Seems to me like you are reading space consumed.

it might free some space, but not much.  It will enhance performance, the amount depends on the condition of the drive.  defrag will not replace deleted files.