Show User Library Directory in Mac OS X 10.7 Lion & 10.8 Mountain Lion Modern Mac OS releases from Mac OS X 10.7 & OS X 10.8 onward default to hiding the users Library directory, this is probably to keep people from accidentally deleting or damaging files that are necessary for OS X Lion & Mountain Lion to function properly. That is fine for novice users, but for some of us, we want to be able to