I have a Time Machine backup from a different computer, but I don't have access to certain folders (it shows the little red roadsign that access is not permitted). I guess it has to do with ownership/permissions of the folder.

How can I access those files? Obviously sudo or chown don't work, since I'm on a different machine.

  • Are you comfortable opening terminal and typing ls -l and then dragging a folder from the backup drive where you see the prohibited sign to get some details which user ID is needed to browse it?
    – bmike
    Mar 18 at 18:32
  • I couldn't even ls -l because the proper credentials are needed for this. However, see my answer for the solution!
    – Pim
    Mar 20 at 15:48

2 Answers 2


You are correct. The unix heritage of macOS has the concept of a user ID / owner and by default, you can't see another user's files. The first user account is 501, then the next 502, etc... So either your current user or the one backed up has a different user id.

Don't change the permissions on the disk as that can break things greatly. Instead, let's see if we can sort out making a new user that matches the old ID or if you can try mounting the disk to "ignore permissions"

But even before that, have you tried browsing that Time Machine disk using the built in tools to restore those files to a place on your current computer? The admin tools / password will automagically remap the files to belong to your user IIRC.


So, the solution is simply to authenticate on the disk by using the "Get info" (cmd-i) window on Mac OS. When you click the lock, it will prompt for credentials. Once those are entered you can browse the backup disk normally.

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