This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
Some II users like to download Apple II files to a PC and transfer them to a Mac for eventual transfer to Apple II ProDOS diskettes. Unfortuantely, under most circumstances, PC Exchange writes files onto ProDOS disks as extended typeless ($00) files which are difficult to work with on the Apple II. What you need is to get hold of a Mac application named "ProTYPE". You drag 'n drop the files on ProTYPE, then copy 'em to the floppy. The files will work then. By: Rubywand