Do you have the special AEHD device driver loaded that came on the floppy disk with the drive? If I remember correctly it won't work in high density mode without it. Also, the High density mode is an emulation of type, in that it will actually show two floppy drives in Workbench... One drive is the first 720k and the other is the next 720k giving you the total capacity of the high density disk that you are using... Hope this helps...
