I am using a Mac Book Pro with El Capitan installed. Yesterterday I was trying to change a file permission and I made a very big mistake.

This is the command I issued

sudo chmod -R 777 /

After issuing the command the system began to give many system errors. I restarted my laptop and now it keeps stack at the apple logo with the progress bar.

I have been able to go to the single user mode, buh I dnt know how to get the laptop to boot normally.

Anybody with an idea on this can help me. Thanks


Boot to recovery HD and just reinstall the OS.

This is done by Holding the Command and r keys down while turning on the Mac. You will then be given the option for reinstalling Mac OS. This will not delete any of your files, merely replace just the damaged Mac OS files.

All permissions will be fixed on the system side - no apps get deleted, no user accounts or date is deleted.

Worst case, you'll need to set up a new admin user on the machine once it's reinstalled (boot to single user move and delete /var/db/.AppleSetupDone) to finish changing permissions on your user folder.

You could also boot to internet recovery if normal recovery fails.

  • pls what do u mean by reinstall the OS? I am asking because I know that reinstalling the OS again will delete everything from my machine – George Mar 21 '17 at 13:59
  • I have made some edits on the answer that should clarify your questions. – Steve Chambers Mar 21 '17 at 14:04
  • I want to kindly confirm this so I dnt make mistake. I currently dnt have a copy of the OS. And when I go to the utility, I see Reinstall a copy of OS. Should I still continue following the process? At what point shld I stop the process? Thanks – George Mar 21 '17 at 14:18
  • @SteveChambers any knowledge whatsoever? – George Mar 21 '17 at 14:45
  • The OS is downloaded from Apple's servers, so you need an active network connection. Also you'll get the OS that came with the computer, so it may be an earlier version, which you can then upgrade if you like. Just reinstall the OS and let it fully complete. – Steve Chambers Mar 21 '17 at 14:57

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