MAC fails to boot

October 2016


What can be done when a MAC refuse to boot and that the main page displays a white backgroung with a circle in it?


Perform the following manipulation.
  • Restart your MAC and hold down the 4 keys: ALT-CMD-P-R and keep them pressed up to the 5th 'beep' (the startup sound). Then release the 4 keys and let the MAC and then boot normally.
  • If it does not work, go to step below.

Repair system files

For this, you must restart the Mac in "single mode" by holding down the Apple key and S (or Cmd and S, depending on the keyboard) until a black screen with white text appears.
  • When nothing moves make a carriage return to move to a new line starting with:/ root#
  • Now type the command fsck -yf then do a carriage return to run the command.
    • Note 1: case sensitive and spaces
    • Note2: single mode, the keyboard is in QWERTY mode, better make numeric keypad to type the dash character.
  • The process will take a few minutes.
    • As long as the results contains "File was modified" repeat the fsck -yf command and do a carriage return.
  • Type reboot and do a carriage return
  • The Mac will restart normally.

Notes that

If this is still doesn't work, then use the Mac OS X installation DVD/CD and restart the Mac holding down the
  • ALT key to select the CD/DVD as primary boot device,
  • A system repair from disk utility will then be perform.

Thanks to Ritchi for these informations!

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