I would NEVER defrag an HD in an arranger from a Mac. EVER...

They are meant to be run by PC's, formatted by PC's. Simple file transfer at most is all I would trust a Mac to get right (and I use one!).

In fact, I wouldn't even try to defrag an arranger HD from a PC unless I had personally contacted the manufacturer, and asked which utility to use, if anything...

A better solution might be to completely back up the HD's contents, and then erase them all from within the arranger. Then load them back in over this cleaned out drive, and everything should be de-fragmented.

Don't EVER use PC utilities on arranger drives unless you are absolutely sure that it is OK to do so. Several members have managed to muck up HD's trying to do this without firm instructions. Never ASSUME...