I had a folder named private in one of my projects and had to change the permissions of it via chmod, however, instead of "private" I did "/private"!

I am an idiot and can't figure out how to get it back. My shell is all messed up now and I am trying to restore the /private folder via time machine and no luck! It starts but then says "Security agent may only be invoked by apple software"

I know this a HUGE mistake and any help would be appreciated. I am on el capitan

  • Possible duplicate of How can I get back a system file after deleting it from my Mac?
    – grg
    Dec 23, 2016 at 21:20
  • What version of OS X If 10.11 or later this surely should not be doable with default settings of SIP
    – mmmmmm
    Dec 23, 2016 at 21:56
  • Has anybody tried the easiest thing in the world yet? Use Disk Utility to repair permissions. Dec 23, 2016 at 22:11
  • @SteveChambers el capitan does not have the repair permissions in disk util anymore
    – Ronnie
    Dec 30, 2016 at 18:52
  • Whoops, forgot about that, try this in terminal(without the quotes) "sudo /usr/libexec/repair_packages --repair --standard-pkgs --volume /" Dec 31, 2016 at 13:38

1 Answer 1


If you have a backup and want to learn how to finesse this, try booting in macOS Recovery. Then:

  • From the Utilities menu, select Terminal.

  • Run:

      chmod u=rwx,go=rx "/Volumes/Macintosh HD/private"
  • Reboot.

This will set the permissions to read-write-execute for root and read-execute for anyone else.

Alternatively, try this or see the answer linked by @grgarside (this).

If you don't have a backup or don't want to make things worse — from macOS Recovery, a quick reinstall of the OS will re-write everything that's critical for the system to run without erasing any programs or user data. Don't mess with anything but a clean reinstall unless you are sure exactly how you messed things up and are confident you won't do more damage trying to fix it by hand.

  • I've edited this to mention a backup and the clear "right answer" in my opinion - just reinstall the OS on top of the broken OS. Your system cannot run without proper permissions and ownership of /private - better to cleanly reinstall unless you have time and inclination to "experiment" without risking your data.
    – bmike
    Dec 23, 2016 at 22:49
  • 1
    Agree on the "inclination" passage, but changing permissions for /private as described won't worsen the state of the system. At the very most, the OP can still reinstall. I'd leave that as the last (time-wasting) option.
    – giucal
    Dec 23, 2016 at 23:13
  • @guical - 💯on your option being elegant and minimal. if you're skilled at terminal, you probably already know how to fix what you messed up and won't ask here. I'm "editing" for the vast majority of the user base here. My guess is Ronnie is such a user and will give you the answered check once they sort things out.
    – bmike
    Dec 24, 2016 at 0:20
  • So I was able to boot into recovery mode and when I try and run sudo, it says command no found. I must've really messed things up. I am doing a full restore from time machine in recovery mode and so far it looks like it's working. It has about an hour and a half remaining. I am going back to the previous day before I goofed.
    – Ronnie
    Dec 30, 2016 at 18:54
  • My fault, there is no sudo in recovery mode, and there is no need for it, since you are indeed root. The correct command would therefore be chmod ..., without sudo. Anyway, a restore should work.
    – giucal
    Dec 30, 2016 at 20:27

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