Macbook Pro Retina (mid-2014) shutdowns with -128 code

batterykernel-panicmacbook promemoryshutdown

I have a Mid 2014 Macbook Pro, which was just serviced at Apple (battery replacement). While they were replacing the battery they cocked up the main board with CPU, RAM etc and replaced that for free. Here I thought – nice service, I got my old CPU/RAM replaced, almost like new my Macbook! 😀

Obvisouly in the shop no issues were present for the n-minutes I examined it. Home, under a week of usage, started shutting down in a most peculiar way:

  1. Screen goes black, but still remains backlit for 30 or so seconds.
  2. Then the laptop fully shuts down

No apparent reason was found. So I went throught SMC and the memory reset procedures – no luck. Apples startup diagnostics alaso did not show anything.

Looking at shutdown logs I get latest a kernel panic with code -128 (RAM issues?):
kernel: (AppleSMC) Previous shutdown cause: -128

So I wonder wtf is actually happening. I manage to write this entry while in safe mode, could it be a software issue still? Not likely installing unreal engine and quixel mixer caused the cockup… But am at a loss if -128 can influence that in any way.

Any tips? (Not sure if Apple provides warranty on repairs in case it is an actual RAM issue)

Best Answer

Here is a post suggesting disabling the Thunderbolt Ethernet Driver solves the issue.

Another post suggests the nocrashmbp utility which says 2013-2015 MacBook Pros are susceptible:

The CPU has several power states and voltages. Some CPUs have become unstable at the extremely low voltage on one of it's cores. The CPU will sometimes briefly dip into that power state, and if it happens to be on the core wherein it is unstable you will see the “silent” crash. Screen goes black, a few seconds later it dies completely. This condition was observed with external test equipment, as well as through internal cpu voltage monitoring.

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