What is the disadvantage of using UFS file system on an external drive used to hold user home directories? I have found one advantage: It is not possible to set "Ignore ownership on this volume" on a UFS format drive while it is on an HFS+ volume. The problem is that several users share the Mac and I'd like to insure that one user can not access another user's files. This is easy on the boot drive but Mac OS allows any user to decide not to enforce ownership on an external HFS+ or PCFS drive. So why not use UFS?