Hi! im not sure about this..but i guess you are talking about one of the options for copying Amiga disks, right?
I mean, you may have some other options instead of DOSCOPY, such as DOSCOPY+ and/or NIBBLE? If that is ok, then is just a way of copying amiga disks only. I never tried to copy a pc formatted disk using X Copy III (i only have previous versions of that program, but i assume they are all quite the same thing)
Regards
Sebastian
