This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
You are most likely to succeed with an older Mac. However, even older Macs that have built in compatible 800k (DD) drives will often produce a IIGS diskette that is not quite right-- such as a diskette that should boot gives the "Unable to Load ProDOS" error message. If you have an older Mac that should write standard IIgs disks properly and it does not, clean your Mac drive and keep trying. For instance, you may need to extract a diskcopy archive a few times for the disk to write properly. Newer Macs are, generally, less likely to succeed. Some Macs, such as iMacs with a floppy drive option, cannot format IIgs-compatible 800k diskettes. ---------------------------- By: Simon Williams There was a thread discussing the impossibility of creating bootable ProDOS disks from a Mac with a 'force-feed' floppy drive. Seems it ain't necessarily so. Using Bernie ][ the Rescue on a G3 iMac with a cheap USB floppy, I first create a Diskcopy 4.2 800KB image, which I copy to a 1.44 MB diskette with the finder. Then I transfer the disk image to a PowerPC 6100/66 which has the non-auto- inject disk drive (running System 7.5)... copy the image to the HD. Format an 800KB ProDOS disk with the finder and then use DiskDup+ to copy the image to the floppy... So far it's worked perfectly. I've made both GS/OS 5 & 6 and ProDOS startup disks this way... :) The one oddity is that GS-formatted disks take a long time to write, whereas the ones formatted under MacOS seem to write much quicker... DiskDup+ is the key. I wondered myself why I hadn't tried Diskcopy... so I tried it -- without success.