MacBook Pro 15" Retina mid 2014 random shutdowns My MacBook Pro (15-inch, Retina, Mid 2014, macOS 10.13.1) shuts down randomly.


It shuts down suddenly when on battery
It shuts down a little more rare when connected to AC
It works almost fine when in safe mode
It works perfectly while I install macOS
It works fine when I have an external screen connected and a YouTube video is playing there (it is my last solution to make work on this comp) but…
It shuts down with external screen connected but no video playing. It happens in the moment of going to sleep mode. Or while it is in sleep mode, I don't know exactly. So maybe video playing helps in that it doesn't go sleep because of video.


Not working possible solutions, I tried:


reset SMC
reset PRAM
login with newly created user
reinstall OS X over old OS X
reinstall OS X entirely
replace thermal paste. I found that one screw "hole" was unlinked from board. So my heat sink is fixed with 3 screws. But it touches bottom plate when it fixed. So it is kind of tight to CPU anyway. It can be a problem though. But why stress tests passing then?! Read next.
monitor temperature (no overheating)
monitor battery (no problems)
run Apple Hardware Test (no issues)
look at Console App. Logs are not saying anything important or like. On old OSX and newly installed. Logs just cut on time of shutdown and then line BOOT_TIME.
Stress test CPU. 8 times yes &gt; /dev/null &amp; in Terminal. And all cores are 100% loaded. Temperature raises, fans in turbo mode. No shutdown, no problems.
Stress test GPU. Open Webgl demo page in browser with 10000 fishes in awuarium. No problems.


Some lasting ideas:


Replace battery (not easy and fast as I need. A lot of work pending)
Go to Apple and leave my only computer for unknown period of time. And I have no warranty of course. And I Googled a lot of stories when Apple couldn't find a issue and people had to replace main board for big money and time. Very bad.
Buy new computer. A bit difficult for me now.
I have read in some places, that this problem doesn't appear in Windows in Boot Camp! I even downloaded Windows 10 to try, but not yet. Anyway I need my favourite macOS, not Windows.
Somewhere I read that it is some problem because of low voltage mode on CPU. It causes some 'unstable' regime in CPU and so system halts. It was only little info about that. It seems like real path to solution. But I don't know how to investigate this more.


A little History


2 months ago: I changed battery with one from aliexpress (china market). It was described as OEM Apple. It is quite the same and it detects with coconutBattery as Simplo manufacturer. I Googled and they say it is like OEM.
1 month ago: I have replaced my charger cord with one from fault charger. With MagSafe 2 connector.


The beginning

I took my MacBook to the bed and it shut down unexpectedly. It was like screen gone black, but backlight on. Then fans went full throttle slowly. And then it shut down completely. I pressed power btn and it started as usual. No messages. No warnings.

Then it worked for some time (maybe half an hour) and story repeated.

I decided that it is overheating because of bed. Took it to the desk. And problem repeated in some time. I began to google this hard. And play with problem to nail it down. 

In the process I found that it works fine in Safe Mode (almost, but I had couple of crashes even in safe mode) It works fine when I reinstall macOS. All long 2 hours of downloading and 1 of installing it worked. After long google I found that it works better with external screen connected.

Current situation

So to recap. MacBook is failing almost always, except when I have external screen and video on it.
https://outluch.wixsite.com/rmbp-crash


Disable SIP (csrutil disable from Recovery)
Move AppleThunderboltNHI.kext


sudo mv /System/Library/Extensions/AppleThunderboltNHI.kext \
/System/Library/Extensions/AppleThunderboltNHI.kext.BAK


Reenable SIP (csrutil enable from Recovery)