I installed PC Ram into my Early 2011 15 inch Macbook Pro (Ver. Sierra 10.12.4). It works great but occasionally restarts without any warning and sometimes, when I turn it on, this code appears. It is gone if I do a hard shut down and then start it again. I did a hardware test (pressed 'D' on restart) and that hardware test said there were no issues. Thoughts???

Type of ram - Komputerbay 16GB Dual Channel Kit 2x 8GB 204pin DDR3-1600 SO-DIMM 1600/12800S (1600MHz, CL11) for MAC and PC

Image of error message is attached.enter image description here

  • If you remove said memory, does the problem go away? However, looking at the first line being a page fault, this is related to swap space which is related to the hard drive. – Allan Jun 20 '17 at 14:25
  • That said, I am not a fan of "off brand" memory or components. Go with Crucial, Kingston, PNY, Micron, Samsung, etc. Have a look at this answer for details: apple.stackexchange.com/a/229377/119271 – Allan Jun 20 '17 at 14:33
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    @Allan In this case the "page fault" does not mean that it has something to do with swap space or the hard drive. User space page faults are normally related to swap space, kernel space page faults are definitely not. They are caused by either bugs in the kernel or hardware error - usually memory or bus errors. – jksoegaard Jun 20 '17 at 17:26
  • @jksoegaard Either way, it's memory or hard drive – Allan Jun 20 '17 at 17:59
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    @Allan No, it's very improbably that it is hard drive related. There's nothing to indicate that. The link from "page fault" to "hard drive" in this case is flawed - it simply has a different consequence here, than a "page fault" in a user space program. – jksoegaard Jun 20 '17 at 18:29

If the problem started occurring after installing the RAM, it is most probably caused by the RAM. Issues with RAM can be "spotty", meaning that it doesn't necessarily fail all the time - but just randomly or when the system is hot or similar. Therefore the RAM might be flawed even though the system passes the hardware test.

The error message in the screen shot shows a page fault within the kernel. This is typically caused by either a bug in the kernel, or a hardware error - usually faulty RAM or bus/CPU errors, but the latter is less likely.

As this happens during boot-up and a laptop is usually comprised of only expected hardware components - it is likely to be a hardware error.

If you have any external devices plugged into the laptop, for example Thunderbolt or USB devices - try unplugging to see if that solves the problem. Then the cause could be a buggy kernel extension.

You can try downgrading to an earlier version of macOS if you're certain it is not a hardware error. If it is a kernel bug, the bug might not exist in earlier versions of macOS.

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