When you dealing with external files or copy files into your hardrive in Mac OS X, I believe you facing this issue “Unable to change files” or “Operation not permitted”. Even you already use “sudo” but you don’t permission to change permission or owner for this files.

This is happen when we dealing with files with other filesystem. The solution is simple and straightfoward :

After you using “chflags”, you can set “chmod” or “chown” without any problem.