Can anyone tell me how to remove mp3 files from unit hard drive?

they are not mp3's, the z1 rips it into the HDD using its own compression format.

as for deleting songs off your HDD, just play the song and go into the options button and hit delete track.

Coocho is as Coocho does!

go into the options button and hit delete track.

I tired it - cannot locate an ' options ' icon/button

I got the online owners manual and found this statement ...

"Only the playlists and tracks in the [Albums]group and the [My Favorites] group can be edited."

I have now figured out how it works.