It seems to me that one has to have an Apple 3.5 drive to format in HFS. The Unidisk 3.5 does not have the HFS option is the Standard File Dialog box. This is based on two indentical ROM 01 systems, one with Apple 3.5 drives and one with Unidisk 3.5 drives. And I have no idea on 3rd party drives. Jim ----- The Palmtree BBS 310-453-8726 v.32 Inet: jpoore@pro-palmtree.cts.com