My Macbook pro (early 2011, upgraded to 10.11) started behaving strangely lately. It started randomly crashing multiple times of the day, and the only information I've been able to find is the following message in the logs.
Oct 26 10:07:01 localhost kernel[0]: Previous shutdown cause: -128
Any idea what might have caused it? I've looked up the cause code, but it didn't provide me any additionl information and I couldn't find anything online.
Edit: I did two memtest runs and they both returned no errors on the memory. I've also tried swapping the memory banks around without any improvement.
AHT same thing, doesn't find any error.
Best Answer
Please make sure you also check your Macbook for excessive dust inside!
I have a Macbook pro which shutdown randomly (and gave the shutdown cause -128 error). When I cleaned the build up dust it started functioning normally again!
I just removed the backplate and used a can of compressed air to clean it. Check https://www.ifixit.com/Device/Mac_Laptop to see how you can remove the backplate of your model.
PS: Try not to touch any parts inside, because of static discharge