Hi All, I have an iMac, 3 MBPs running Lion and Snow Leopard. In all of them, su command works just fine and of course I had no issues with them for many years. I just bought a MBA 2011 and it came with Lion 10.7 which I updated to 10.7.1. The su command just simply refuses to work. It display 'su: sorry' as if I typed the wrong password. 1) I tried my own account password which is an administrator. Didn't work 2) Enable root account and set the password. Didn't work (I checked in my all other machine, don't need to enable root as the 'enable root' is still avaialable where as if it has been enabled only 'disable root' option will be displayed 3) Created another account (admin) also didn't work. What did I miss here?