The Apple IIGS is designed to be used with the vast majority of Apple IIe
hardware and software. However, there are some design differences that will
cause some products to be incompatible with the Apple IIGS.
Some Apple ProFile Interface Cards work incorrectly in an Apple IIGS and
cause the information on the ProFile to be inaccessible. To avoid problems
when using a ProFile in an Apple IIGS, either modify the interface card or
obtain the new version of the card.
The Apple IIGS bus' higher 'noise' levels create the problem. The 'noise' is
passed on to the ground traces on the ProFile interface card and will
eventually (after use) corrupt the directory of the ProFile, rendering it
invisible to ProDos and inaccessible to the user.