I can no longer log into my Mac after “sudo chmod 744 /”

0

Right after I executed:

sudo chmod 744 /

on my Mac, everything on my desktop is gone, and I can no longer open any applications or folders. So I pressed the power button to restart my Mac, but then the windows just freeze in the user log in page. Please help because I have lots of important files in this Mac.

I'm pretty sure it's simply because of the sudo chmod 744 / permission change via chmod and not anything else.

I assume this because I also have a Ubuntu machine, and exactly the same thing just happened when I ran that same chmod!

Now I have two unusable/unbootable systems now due to the same issue. How can I fix them?

user9607441

Posted 2018-05-23T00:39:25.663

Reputation: 13

@dsstorefile1 thanks for you reply.. The thing is I do not have any backup, and I can no longer log in to my MAC, so I can't get to the terminal.... – user9607441 – 2018-05-23T00:49:44.560

@dsstorefile1 Thanks. Do you mean holding Command+R and go to Disk Utility to reinstall it?? Thanks again! I saw this option but just wasn't sure if all my user data will be preserved – user9607441 – 2018-05-23T00:55:24.590

@user9607441 I would actually recommend you boot into your recovery partition on the Mac using “Command+R” and just repair the disk if possible. Also, you say you have no backup but also no clear reason why you would run sudo chmod 744 / on two machines? – JakeGould – 2018-05-23T01:15:45.523

@JakeGould I'm currently in the process of reinstalling a new macOS(after pressing Command+R), so I may not be able to perform that.. – user9607441 – 2018-05-23T01:17:56.193

2@dsstorefile1 Thank you so much!!!!!!!!! Problem solved after I reinstalled macOs!! And all my files are still there! What a relief!! – user9607441 – 2018-05-23T02:01:35.817

1@user9607441 First, congrats on saving your data! Now please, invest in at least a USB backup drive for your setup. That said, I believe the reason why the OS reinstall worked was because the process runs “First Aid” on the destination disk before the OS files are actually reinstalled. Posted a full answer here so others can benefit from this painful experience. And again, congrats on recovering the data! – JakeGould – 2018-05-24T18:17:08.460

Answers

1

Hope is not lost!

If you are able to boot from the macOS recovery mode—via rebooting and holding down Command+R, you have two options:

  1. Repair Disk Permisions via Disk Utility: This should be the quickest and easiest way to solve the issue. Simply launch “Disk Utility” then select the partition that has messed up permissions and hit “First Aid” from the menu options. Wait a bit and “Disk Utility” should be able to detect the messed up permissions and repair them.
  2. OS Reinstall: This is a more radical—and time consuming—option, but it should work. The macOS installer will check the destination volume for an already existing OS—irregardless of permission state—and then be smart enough to reinstall on top of that setup without affecting the user files you need. That said—and to the best of my knowledge—the reinstall of files is not what solves stuff like this. Rather what happens when you upgrade or reinstall macOS is the process will run “First Aid” before doing anything else. That process will fix the permissions issue and then new OS files get installed.

So at the end of the day, running “First Aid” via “Disk Utility” will repair permissions in macOS. In Ubuntu? Unaware of an equivalent process, but if anyone out there knows of a way to reset Ubuntu permissions when they get messed up like this, please feel free to post an answer.

JakeGould

Posted 2018-05-23T00:39:25.663

Reputation: 38 217

Asked: 2018-05-23T00:39:25.663

Viewed: 178 times

Active: 2018-05-24T18:19:07.087