Files skipping, glitching and crashing after transfering in DiskMode (Ipod5G)

[Sf0rce]

  For some reason some of my files get corrupted after putting them into my Ipod. Some play and skip after a few seconds,
some just glitch and make the machine slower. I also notice that the OS itself freezes sometimes (CPU problems, or bad files?), and I even got
some white screen errors  - something about dividing by zero and stuff like that).
At first I discovered that moving stuff outside diskmode was bad and thought that the problem lied there. Unfortunately,
even using the original firmware, some of my files are getting corrupted. I just copy and paste folders containing .mp3 and .flac
using W10 File Explorer, and I think that should work.

  Could it be that the Hard Drive (I have not modded the device - it uses the original 30Gb HD) is broken, or should I use
dedicated software to transfer files in order to avoid corruption?

  I think it's good to note that the a given file always crashes/skips/glitches at the same place, i.e. not in an aleatoric manner.
Tried overwriting some of those with the exact same file, and sometimes it solved the problem, other times it remained
 corrupted (probably crashing/skipping/glitching in other places than before)