10% lost in files

I defraggled my 2TB hard disk when it was over 90% full (100MB free). After very looong period and couple times stopped and started again, because power save was on and stopped hard disks and I turned computer off, but only by using "stop defraggling" I noticed that many of files are corrupted and cannot be copied to another HD. Why?

corrupted how?

are you getting CRC errors?

how many files are we talking about?

you are assuming (maybe correctly but maybe not) that DF is to blame, any reason not to believe those files were already corrupted before the defrag?

Edit: is it an internal or external drive?

Exactly how the files corrupted? Are you getting disk errors when copy/paste them? What kind?

They are wav- files and seems that part of them are corrupted so that information is wrong. You canĀ“t copy them and when you play them with player it stops when song reaches corrupted place. When opening them with wav- editor the curve is just on the top in corrupted place.