Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

My MacBook Pro shuts off randomly. I'm running OSX. This happens whether the battery is plugged in or it's running on power.

What could be causing this?

share|improve this question
Is this a unibody or non-unibody MBP? – ricbax Oct 30 '09 at 20:28
You say both “shutdown” and “shut off”. “Shutdown” usually means the normal, orderly close everything and power off sequence, while “shut off” sounds more like a sudden power loss that results in a from-scratch restart. Or maybe you mean the machine is going to sleep (status light fades in and out)? What is actually happening? – Chris Johnsen Oct 30 '09 at 23:13

It could be bad RAM, or a faulty logic board, or bad power circuitry. Someone that sees lots of them (like a Genius at an Apple store) might be able to recognize the particulars and narrow it down.

share|improve this answer

Off the cuff answer with as little information as is provided? Heat. The CPU or GPU getting too hot will cause the machine to protect itself by turning off.

share|improve this answer
I had an overheating problem, /after/ having a motherboard swap, on a PowerBook. The machine would go to sleep, when it happened. The GPU heatsink had been re-fitted incorrectly. – jrg Nov 3 '09 at 14:58

My MBP 3,1 is on logic board #3. When the first two began to fail I would get lots of random kernel panics. Not 'shutdowns' or 'shutoffs' but the lovely multi-lingual kernel panic screen.

If your laptop is just switching off: The only time this has happened to me is when the CPU/GPU are wayyy too hot as mentioned by Chris Johnsen.

Have you checked your logs in

share|improve this answer

I run into the same type of issue where all of a sudden my Core Duo MBP (1.1) just shuts off. This typically happens when I am running something intensive like handbrake to reformat video.

I have looked into the console logs and the application logs from HB. There doesn't seem to be any indication that the system is reporting that it is shutting down or that anything has cored. Just "Lights out good night.". I suspect that there is some self preservation going on here.

Jan 29, 2010 update:

Ran a little experiment yesterday. Ran Handbrake ( which usually shuts my MBP down). I also ran a utility called smcFanControl. This monitors temps and lets you adjust fan speed. With my laptop on a cooler surface and setting smcFanControl to run fan speed at max. I was able to keep my poor ol' core duo CPU within a tolerable level. My system didn't shutdown. I would suggest moving your laptop to a different surface if running at high CPU usage for extended periods.

As for previous comments on the potential for faulty RAM, CPU etc. You could run through the items in System profiler under the Hardware section and see if anything turns up there.

Good Luck


share|improve this answer

You must log in to answer this question.