I wrote about this a while back on my blog, hackaddict, but it was such a popular post I thought I’d give it a revisit. A lot of people buy used Macs, and they often run into the problem of not knowing the admin password, so here is a way to get around not knowing the admin password on Macs. To reset your OS X password without an OS X CD you need to enter terminal and create a new admin account: (1) Reboot (2) Hold apple + s down after you hear the chime. (3) When you get text prompt enter in these terminal commands to create a brand new admin account (hitting return after each line): (3.1) mount -uw / (3.2) rm /var/db/.AppleSetupDone (3.3) shutdown -h now (4) After rebooting you should have a brand new admin account. When you login as the new admin you can simply delete the old one and you’re good to go again! from “https://gigaom.com/2008/06/22/reset-os-x-password-without-an-os-x-cd/”