When I downgraded from Mountain Lion 10.8 to 10.7.4 (installed 10.7.4 over 10.8), the password for my root or user name were wiped out, they need to be reset with new password, the catch is I can’t login, I can’t change my password.
1. Use myHackLionInstaller to boot from, click tab while booting (counting down) to get to verbos menu. Select myHack installer partition and type -v -s
2. At the Single mode version: type the 2 lines just like it shows:
root# /sbin/fsck -fy
root# /sbin/mount -uw / (must have the forward slash just like the sample).
root# launchctl load /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist
root# ls /Users (to see how many users and their account names).
root# passwd dognmonkey (my account name).
verify new password:
bash# exit (we’re done).
logout (and auto boot to the partition)
Now we can log in with the new password.