Same or different login names for two Macs?

Discussion in 'macOS' started by macstatic, Mar 19, 2015.

  1. macstatic macrumors 6502a

    Oct 21, 2005
    Having two Macs, is it normal procedure to create the same OSX login account name for both machines (and choose a different computer name in the "Sharing" preference pane when connected in a network), or a unique OSX login account for each machine?

    As I'm in the process of upgrading my Mac Pro from OSX 10.6.8 Snow Leopard to 10.9 Mavericks I have the opportunity to choose a new username if needed. My other Mac (MacBook Pro) already runs 10.9.

    PS: would different usernames (or changing the existing one when upgrading to OSX Mavericks) cause access/ownership problems when attaching external drives or accessing my existing home-folder?
  2. Taz Mangus, Mar 19, 2015
    Last edited: Mar 19, 2015

    Taz Mangus macrumors 68040

    Taz Mangus

    Mar 10, 2011
    On all my Macs I create the same account names and name each computer different. You have to be careful when using the same account names on multiple computers. Account ownership is by user ID, not name, so if you have multiple users on one computer, each user will have a sequentially higher user ID starting at 501. If you only have one user per computer then this will not be a problem.

    Attaching an external hard drive from one computer to the next can be an issue when user account IDs don't line up from one Mac computer to the next.

    What I do in these situations is turn on file sharing and mount the external hard drive on the desktop using the appropriate user name. OS X will take care of the translation of user ID. So for instance, let's say I have 3 users on one computer A, Bob (501), Dave (502), and Sally (503). On a second computer, B, I have one user, Dave (501). I turn on file sharing for computer A and mount computer A hard drive on computer B using the user Dave. I can transfer files back and forth as the user Dave because OS X will safely manage the user ID translation from 502 to 501 and vice versa.

    Now if I had a external hard drive attached to computer B where user Bob (501) had created some files, then mounted that same hard drive to computer A, those files created by user Bob (501) would now have user Dave (501) ownership on them on computer A. That is because of the overlap in user ID 501 on computer A and B but the user names are different.

    I hope this answers your questions.
  3. macstatic thread starter macrumors 6502a

    Oct 21, 2005
    Yes, I have more than one login account on each computer.
    So in order to avoid any problems I should go to the "Accounts" preference pane, check each user account's "Advanced options" and see that they all have a different ID (change them if they do)?
    I suppose this also means that I need to compare the user IDs of each computer as well (if they have the same login account name) so as not to get any problems?

    Could I also just do a Finder "Get info" for the particular external drive and turn on "Ignore ownership on this volume"?

    As for installing OSX from scratch and having the user "home" folder relocated to a separate drive (as you've described earlier, here), if changing the login name since last time, would I have to do a "get info" for my old Home folder, then add the new login username (pressing the + at the bottom left) with "read and write" permissions and finally "Apply to enclosed items" which would effectively allow both the old and new username to access it?
  4. Taz Mangus macrumors 68040

    Taz Mangus

    Mar 10, 2011
    I would not suggest that you bother with knowing the user IDs. Turning off ownership on a external hard drive is a good way to share an external hard drive. I do this with a external hard drive I have attached to one of my Macs that multiple users use. I would not suggest you mess with adding more access rights to user accounts.
  5. macstatic, Mar 22, 2015
    Last edited: Mar 22, 2015

    macstatic thread starter macrumors 6502a

    Oct 21, 2005
    I did unfortunately have to mess around with file ownerships because of moving the old user's home folder (which had a different username than the one I've used now when installing OSX Mavericks (the old one, with all the support files, settings, prefs etc. has been copied to the new home folder as I'm trying out the various newly installed apps with the old data, prefs etc.).
    I changed the ownership of the various folders (and their contents) using Finder's "Get info", but now everything's a mess, so how do I make it right? Here's my setup:

    As far as I see I need to fix the following:

    • "MacOSX" drive: OSX, Apps and administrator-user home folder (this one is probably OK though, and I've used Disk Utility to check/fix permissions which I believe should affect the boot drive)
    • "Data" drive:
      • New Home folder and contents (/Volumes/Data/Users/username/)
      • The "Users" folder created on the same drive (/Volumes/Data/Users/)

    Although there's a lot of online info to be found on this it's often quite conflicting and confusing. It appears you know what you're talking about, which is why I'm asking :)

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