Updates to Files On-Demand on macOS

Ken_Tryon  I'm not sure I was clear on what I mean by enabling and disabling ownership - it is not ownership of the drive that is set, it is whether ownership of the files ON the drive is enforced. When the disable flag is selected, any file on the drive appears to be owned by the current user. That does make it easier to transfer data between computers - but it is contrary to the way ownership is treated on every other *ix/ux system I've used. In my past experience, files on a removable drive were still shown as being owned by the user on the local system with the same UID as that of the user who actually owns the files. In other words, the files are owned by a unique UID and that UID will appear on any system if you do an ls -an (or the equivalent flag to display file and group owners as numerical IDs).

The other thing about this flag is that in Apple world, it is supposedly set in a database on the local computer and is not stored on the removable disk itself (again, according to the diskutil man page). The default for removable media is claimed to be disabled. I'm having trouble reconciling that with my own experience, though, since both volumes on my external Passport HD show ownership as being enabled, even though I never changed that flag for that volume from the default.

To change a user's home directory, you need to be logged in as a different user with admin privileges. Then, in System Settings -> Users and Groups, you right-click (or control-click) the user you want to manipulate, and select Advanced Settings. There's an option in Advanced Settings to choose a different directory from the current one. You then have to reboot for the new setting to take effect. To move my home folder, I used the ditto(1) command because it is documented to preserve everything in a directory - it copies both data and resource forks, and preserves permissions (including ACLs and extended atttributes) and *ownerships* - EXCEPT that if the target volume has ownership disabled, every file and directory transferred ends up owned by 99:99 (unknown:unknown). The current user doesn't see that corrupted ownership when doing an ls however - only root sees the actual file ownership on such a volume - so the problem can be difficult to detect. This is what happened to me - and because I had transferred my home directory back and forth several times before I discovered it, I had no copy left with the correct ownership and had to chown -R my entire home directory back to what it should be to correct the problem.