Changed "Get Info" permissions, now system won't load

As a second option (the Command-S single user mode with chmod should still work) - I have just tested and proven that you can *also* get this to work by booting the mac into "Target Disk Mode" (i.e., hold down just the "T" key on boot) and then connect either a Thunderbolt or FireWire cable to a *different* machine - then you can do the same chmod commands after doing a "cd /Volumes". We found this to work with Sierra level machines, when we couldn't get the single user mode working easily (it hung too).

The only solution is to reinstall OS X. Hold Command and R keys while your Mac is starting and reinstall OS X, so you should be able to access to OS X again. If not, you have to erase the disk with Disk Utility and reinstall OS X again, losing all the files you didn't back up

Restart with the Command and S keys held down and run the following:

mount -uw /

chmod 1755 /

exit

(77397)

Keep going; that message means that some cleanup was performed on the drive.

(77398)

Thanks Niel. You saved my day. Cannot thank you enough.

simply brilliant!

Worked somehow. Thanks Niel.

Thank you so much Niel!!!!!

Another workaround that just saved my day:

I connected my MacBook Pro to another Mac & started up in target disk mode - from there I was able to reset the harddrive permissions.

After playing around with the permissions for so long, I am just slightly confused:

what are the recommended settings for harddrive permissions? Obviously not "Everyone: No Access"! ;)

dude you saved me from have to go to the genius bar two days in a row with this answer. Luv you man

I have an IMac i5 with OS 10.8.5. Just one of the several external USB drives has "custom" permissions set in its Get Info window. I can click the unlock icon, enter my password, but I can not change the permissions. Will this sequence of terminal commands allow me to unlock and change the permissions for just the one external drive?

mount -uw /

chmod 1755 /

exit

If yes, at what point do I specify which drive I want to change?

The drive to be changed is NOT the boot drive.

Thanks for your help.

gbof

Hi,

I have the same problem by applying accidently the "permission No Access to Macintosh HD icon. After I restared the computer, the apple icon loads, the the spinner starts to show the system loading, then it freezes with the grey screen. I've restarted multiple times and tried via command -R and checked out disk utilities - disk and permissions verify fine. I tried to load OSX Lion from the Apple website (by Command+R procces), entering my Apple ID and Password but I got the message that my software (OSX Lion) was not bought by this ID.

I precise that I bought my iMac used with OSX Lion already installed on it about 2 years ago.

I am an Apple customer since 2005 and I bought other computer from Apple but this is the first time I have a problem.

I am really stuck and any help or assistance would be realy appreciated.

Thank you and best regards

Such a simple fix, yet it worked for me as well.

I really need to understand permissions better. That's the 2nd time I've messed with them thinking I was "improving security" and I ended up breaking things very badly. Thank You!

Note that I am running Mavericks 10.9.2, not Mountain Lion.