My wife's MacBook Pro has begun shutting down unexpectedly, at seemingly random intervals. This started occurring after I (very carefully) upgraded the machine from 4 GB to 8 GB of RAM and replaced the old battery, which had reached the end of its life.

The shutdowns are instantaneous, while there is plenty of power left. It's as if the power button was held down. It has happened twice when a USB hard drive was connected, but that might have been a fluke. I haven't been able to consistently reproduce the issue.

Does anyone know how to debug this issue, like if there are any logs of unexpected shutdowns that might provide some clues as to what's going on? Any pointers greatly appreciated.

I'm not sure if this is relevant, but the same machine was having a different issue with sleeping until I upped the RAM and changed the battery. This issue has since stopped happening.

Edit: The problem we're experiencing sounds very similar to this blog post.

  • Usually if it just shuts down instantaneously it might be a hardware issue. Run the Apple Hardware Test to check. Wondering if there is something in your Console log just before the shut down. – Ruskes Mar 14 '15 at 17:57
  • Thanks for the tips! I will run the Apple Hardware Test (once I find it). Do you happen to know where can I find the console log messages that are logged when it shuts down? – Leif Mar 14 '15 at 18:05
  • Console is in your utility folder. Note the time when it shuts down, open console all messages and look for that time stamp, copy some 30 lines around it for us to help you reading it. Apple hardware Test is hold "D" when restarting the computer. – Ruskes Mar 14 '15 at 18:12
  • Thanks for the tip! Found Console, going to dig through it a bit. Tried running Apple Harware Test while rebooting with the install DVD and holding down the D-key, but for some reason it won't start. – Leif Mar 14 '15 at 18:17
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    If you need to you can download it from here by choosing your correct model. github.com/upekkha/AppleHardwareTest – Ruskes Mar 18 '15 at 16:23

Here is a Terminal command to find out what is shutting down your computer.

syslog -k Sender kernel -k Message CSeq 'n Cause: -' | tail | awk '/:/{$4=""; print}' | pbcopy

It will save a text format copy to your desktop.

  • Awesome, thanks! I will try that out later on this evening when I get access to the computer. – Leif Mar 18 '15 at 16:15
  • I tried running this, but it didn't output anything to the clipboard or create a file on the desktop. However, it led me to the syslog, and I dumped the entire log for a couple of days when I know the error has occurred with approximate times for the occurrences. I'm not looking through the logs, trying to find clues as to what may have gone wrong (grep'ing for 'kernel' in the log messages). A lot of stuff in these logs, not sure what I'm looking for. – Leif Mar 22 '15 at 21:15

Shut down fix after liquid spill. Well I hope this helps some people. So, I bought this 2011 macbook pro on craigslist for $100. The issue was that it would not stay powered on according to the seller due to a liquid spill so I took my chances. I installed a new SSD and got it to power on. Indeed the it would turn on and then power off. Sometimes it would stay on for hours and other times it would power off before it would even boot up. The number keys would not work and they typed letters instead. What was odd though was that most times when it was on it would open the window that pops up when you hold down on the power button and then shut down on its own. Other times it would shut down with no warning. Another odd thing is that after holding the shift, control and option button (not the power button) it would reset it self like I did and SMC and then I would hit the power button or any key and it would turn on. At this point I was suspicious that something isn't right with the keyboard which might be the source of the shut downs. However, that was a hard fix so 1st thing I did was a new battery. I was hoping that since it still had the original better that maybe thats why it would shut down. So I bought a new aftermarket one for $30 but no fix. So now it was for the challenging mission. Keyboard replacement. I bought a new one on amazon for $20 without the backlight since mine was still working. Once I got everything out I found that the keyboard from the inside is covered with a black plastic cover. So I am thinking wow, it would really be hard even with a big liquid spill for the liquid to reach the logic board. To get the to the point, I go the new keyboard in. Took about an hour and....the Macbook is like new. No shut downs anymore. For those that do not know, the keyboard and power button are connected (once peace) so I am sure thats the reason for the shut downs. Something was shorting out to cause the shut downs. This was actually not a hard thing to do so don't let it scare you. As long as you don't jerk anything out you will be fine. I hope this helps some people. By a new keyboard before you sell your macbook or buy a new logic board. Good luck!

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    Without line breaks/paragraphs, your answer is rather hard to read. Can you please edit and focus on those aspects which actually provide an answer to the problem described in the question. – nohillside Mar 13 '16 at 13:40

Considering the fact that you have a Mid 2010 the Buschar(in the comments) is correct that the Apple Hardware Test is installed on your hard drive not on the DVD. Sometimes the Hardware test will not run on the boot sequence if you have a USB or DVD in one of the ports.

The first thing I would do is perform a fresh install of the OS, that way you can possible remove some possibilities of it being buggy software related, (Obviously don't forget to backup the important stuff)

I know that some of the 2010 models had reports of faulty logic boards and battery connectivity issues and and need the boards to be replaced., hopefully is not the case

  • Thanks for taking the time to provide an answer. I'm trying to figure out why I AHT won't run now. I have no USB devices connected, and it won't start with or without the DVD. I will update this thread as soon as I've figured out why the hardware tool won't run and found the issue. – Leif Mar 18 '15 at 16:18

Did you have unexpected shut downs with the computer before the upgrades? Have you tried reinstalling the original 4gb of ram and see if the problem persists? You changed two things new ram and a new battery. Maybe the ram is faulty or maybe the battery is not outputting the correct voltage. If you did the install yourself, make sure your connections are good and are not interfering with any other components or the bottom case. I have the same computer.

  • No, the computer did not have any unexpected shutdowns prior to these changes, but it was exhibiting another issue which was seemingly related to the battery (ref. link to other related issue in my question). I am now going to reset the System Management Controller (SMC) to see if that helps, if it doesn't then I will also try what you suggested. – Leif Mar 22 '15 at 22:54

I eventually brought the machine to Apple, who ran hardware diagnostics and changed the battery to an original Apple battery, which resolved the issue. My unconfirmed hypothesis is that the first battery I installed, which was not an Apple original battery, was faulty. Apple thought so, too.

What I learned from this experience: Go to Apple support immediately instead of wasting time trying to figure it out yourself. They had it sorted out in a couple of days.

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