I need a Mac that is often offline for confidentiality. Is it possible to store an Admin or General User account on an external disk which I could only login to when plugged in? In my instance it's not as simple as just storing documents/apps/libraries on an external disk; I need the dynamics of an entire account.

A variation of this I'm opposed to is logging in through a local network account server I make and then unplugging the disk when not in use, problem being that it opens more vulnerability's than logging into an account on a thunderbolt connected disk; so one might think this isn't an unheard of solution.

This would be far less of a hassle than having to manage security precaution and system updates on another Mac.

3 Answers 3


You can also install a complete system on an external ssd and when you want use it, you boot your Mac on this external ssd and all users and system informations will be only inside the external disk.


I would copy the entire ~userid to the external disk. Then, using a different account with admin privileges, delete the original and change the default home directory to the new one. After which that user can’t log in unless the external disk is mounted.

Is there any equivalent command for usermod? for more info.

  • Thanks for the comment; changing the home directory should be exactly what I need to do in theory. From searching, I need to copy the home folder of the account to the external disk, then go to System Preferences>Users & Groups>(right click the account) Advanced Options...>Home directory:> and then select the home folder in its moved location, then delete the location of the original home folder. As I said this should work in theory, but I will confirm if it actually works in practice since I'm dealing with a disk that will only be connected on occasion.
    – BBS
    Nov 10, 2021 at 18:29
  • Oh, that's a nice improvement. In older versions (last time I did it, around 2012), you couldn't change the default directory with the GUI.
    – WGroleau
    Nov 10, 2021 at 19:53

Would it work to have the user's home mounted during login? That would fail if the external was not accessible. sshfs can mount a remote disk without root privileges if run by the owner of the mount point. I use it to get local access to my website, but that's a bit different from a home directory.

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