Hello, guys, I did a huge mistake, wanted to change chown for /usr/local/bin and changed for /usr/bin... :-( Now I can't use "sudo" and others... Tried to change it back and operation is not permitted. Help me to solve it please, or tell me, should I reinstall Mac OS? And if is possible to do: 1. Make a backup with Time Machine 2. Reinstall Mac OS 3. Restore with Time Machine Thank you in advance!