How to Reset the Root Password in a Leopard OS X Single User Mode

Single-user mode is a special boot of OS X that minimizes the number of services run. Only the init and mach-init processes are executed in single user mode, meaning that even the hard drive will not be mounted. From this level of access, it is possible to access and modify files by mounting the hard drive. This special diagnostic mode will allow you to change the password for any user, including the root user of the system.

Instructions

1. Hold down the "Command" (Apple) key and the "S" key as your system boots. This will present the single-user mode command prompt, which allows you to influence how the system boots.

2. Type "fsck -fy" without quotes, and press "Return."

3. Type "launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist" without quotes, and press "Return."

4. Enter "dscl . -passwd /Users/user pass" without quotes. Replace "user" with "Root" (or any other user) and "pass" with the new password for the user, and press "Return."

5. Enter "shutdown -r now" and press "Return" to restart the system immediately. The password will be changed on reboot.

References

• Macworld: Reset a User's Password in Single User Mode
• Westwind: Single-User Mode Commands
• Apple: How to Start Up in Single-User or Verbose Mode