Hi My MacBook Pro from 2010 crashed two days ago. Wan't boot OS. "Keys out of order (4, 35253) ** rebuilding catalog B-tree ** the volume Macintosh HD could not be repaired" I'm now trying to copy my data to an external hard drive before formatting and reinstalling OS. In single user mode I'm tying to mount the external hard drive to a folder but I can't create a new folder with mkdir. Saying "File exists". This is no matter where on the disk I try to create one. What is the reason mkdir want create a new folder?