My MacBook has been acting wierd for a while now. Every week or so it completly freezes, meaning I can't interact with the system anymore at all: No mouse movement and no apparent response to key strokes. It doesn't just go away either: last time I left it sitting for about 5 minutes, no luck. In the end I have to hold the power button to reboot it.

How can I track down what it is that causes this? Note that I cannot reproduce the freeze.

Some info: I have a Early 2013 15 inch MBP running 10.10.4.

  • 2
    It can happens for lot of reasons, for example a Ram corruption. You could try a complete Hardware Test: support.apple.com/en-us/HT201257
    – Matte.Car
    Commented Jul 14, 2015 at 14:51
  • Hey @Matte.Car, thanks! I ran the non-extended version, and it gave me an error 4HDD/11/40000000:SATA. However, according to this support document, it's a false alarm. Would you recommend re-running the extended verison?
    – fabian789
    Commented Jul 14, 2015 at 15:26
  • I don't know, I remembered that short test didn't check Ram so that error is already a good result! I would try to run the complete test, it will takes around 50 minutes and it will give you a complete Ram Report!
    – Matte.Car
    Commented Jul 14, 2015 at 19:20
  • I tried the extended test now, but I still get only the above error
    – fabian789
    Commented Jul 15, 2015 at 11:24
  • I give up! You could try going to an Apple Store, they should has more powerful diagnostic tools...
    – Matte.Car
    Commented Jul 15, 2015 at 18:36

1 Answer 1


I had the same exact problems with my 2010 iMac 21.5 running 10.10.4.

Open up Activity Monitor and have it run behind you to check memory pressures and CPU usage. My guess would be your RAM is overloaded, so it cannot make any changes to your system.

Downloading the trial version of CleanMyMac 3 lets you have a nice little memory checker in your status bar. I would recommend (since you cannot upgrade RAM) look for software to optimize your memory usage or alert you when you use too much so you can close needed applications. The internet is full of guides to help lower RAM usage.

Hope that helps

  • "Lowering RAM usage" isn't as simple as it used to be. The new paradigm is "empty RAM is wasted RAM" The OS itself will try to keep the RAM filled & only dump it if needed by a new process. Memory Pressure is the key factor to look for, along with CPU use, of course. Neither of these should ever cause total freezes, though.
    – Tetsujin
    Commented Jul 14, 2015 at 15:07
  • Thanks for the tip, but I'm quite sure that that's not the issue. I have 8GB and they are hardly ever full, and if they are the system gets laggy, it does not just completly give up :)
    – fabian789
    Commented Jul 14, 2015 at 15:13

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