My MacBook Pro kernel-panicked with this message, "You need to restart your computer. Hold down the power button until it turns off, then press the power button again."

The same message appears each time I reboot.

  • 1
    Downvoter is an idiot
    – Andremoniy
    May 16 '15 at 14:19
  • @Andremoniy Be nice. This question doesn't show any research and if someone feels it's not useful, they are encouraged to cast a down vote.
    – bmike
    Oct 12 '15 at 16:30

This sounds as though your system is in a cycle of kernel panics. The first thing to do is to try starting your system in Safe Mode to clear out the system- and application caches and to rebuild the font libraries:


If that doesn't do it, I would next try resetting your PRAM. There may be some boot settings that have gotten messed up. To reset your PRAM, turn off your computer and then turn it on again. Immediately press command+option+p+r until you hear the start tone for a second time, then release it.

If a Safe Boot and PRAM reset don't fix things, you can next try resetting the System Management Controller (SMC). Instructions vary depending on the system, so see the following Apple article for details:


Finally, if that doesn't do it, you'll need to run Apple Diagnostics to determine whether you have a hardware fault. Again, details differ depending on the system, so see the following article:


Best of luck!


Hold down command + r to boot into Recovery Mode, then re-install OS X.


Shutdown your Mac. As soon as you hear the start up tone hold down shift. Then you must release shift key as soon as you see the gray Apple picture. This will lead you to safe mode. Then you restart your Mac to leave safe mode.

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