OS X Lion: Start up in single-user mode

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Start up in single-user mode

To troubleshoot your computer’s startup sequence using only UNIX commands, start up in single-user mode. You should do this only if you are comfortable with UNIX.

  1. Choose Apple menu > Restart, or press the power button if the computer is turned off.
  2. Press Command-S as the computer starts up.

    The computer screen is black with standard white text. You can now run the UNIX commands that you want.

In single-user mode, not all functions of Mac OS X are available. To use the Mac OS X interface or other high-level aspects of Mac OS X, you need to start up in the standard mode.

To switch back to the Mac OS X interface, type reboot and press the Return key. The computer restarts and you see the login dialog or the Mac desktop, depending on your login preferences.

Published Date: Oct 31, 2013