Randomly shuts down when not connected to an external display.

"It's easier than it looks....

https://outluch.wixsite.com/rmbp-crash

How to fix?

1) reboot with CMD+R pressed.

2) open Terminal

3) csrutil disable

4) reboot in normal mode

5) sudo mv /System/Library/Extensions/AppleThunderboltNHI.kext

/System/Library/Extensions/AppleThunderboltNHI.kext.BAK

6) reboot with CMD+R pressed

7) csrutil enable

8) reboot and forget about problem

We turn off buggy driver, that is for ethernet via thunderbolt. It is possible, you dont need that functionality, like me.

Thanks to:

https://forums.macrumors.com/threads/hel...

and personally to Lukas Kroll, who wrote here in comments about that solution found in that forum."

"Lets try this, download this free app: CoconutBattery.

With the system plugged in with your MagSafe power adapter take a screenshot of the main screen then disconnect the MagSafe adapter and take a second after at least 10 mins of being unplugged. Post them here so we can see them.

I'm suspecting your battery is going here or the battery charging logic has a problem. The issue of the display winking out is related as the system is going into power save mode and the system will then go into deep sleep."

"I can only guess, but to me it sounds like the magnetic sensor that indicates your lid is closed is damaged. It goes into sleep but if your monitor is plugged in, nothing happens (as expected). Problem is that the resistor is on the logic board. It is going to be expansive if you do not know much about soldering and that stuff :-/

A workaround would be to go to settings and change the option when the lid is closed to do nothing"

This sounds less like a cooling issue and more like the device is thinking the lid is closed thus going to sleep after a few seconds... whereas when a external display is connected it goes into clamshell mode and there for stays switched on.. I may be wrong but this could be you issue

"After speeding way too much time on this issue, I discovered the source of the problem. This is one of the most evil crashes I’ve ever encountered and behaves not unlike a virus. It is silent and strikes without logs or error messages, leaving you completely baffled as to the cause. If you’re getting a proper kernel panic, then you’re having a completely different problem.

As already mentioned, you can solve this issue by simply disabling or deleting the AppleThunderboltNHI.kext. I also discovered deleting the Thunderbolt Ethernet Adapter profiles as well as any associated NVRAM variables also resolves the issue without disabling the drivers.  These solutions, however, doesn't explain why some MBPs of the same model numbers do not exhibit the shutdown problem, or why it doesn't occur under Bootcamp Windows, or why zapping the NVRAM/PRAM doesn't solve the issue.

When you plug in a Thunderbolt ethernet adapter, AppleThunderboltNHI.kext loads and creates the NVRAM parameters and network profiles. The NVRAM is needed to ensure a network configured connection during Recovery Mode. MacOS loads the driver based on the parameters even without the adapter present to support hot plugging.  This is why clearing the NVRAM doesn't work.  It only clears the values of the parameters, not the parameter variables which clues MacOS to load the driver.

Unfortunately, AppleThunderboltNHI.kext is buggy and throws a fit when it detects there's nothing connected to the Thunderbolt port and silently shuts down the system. The event isn't random as it occurs during certain network operations.

Consequently, by merely plugging your MBP to an ethernet Adapter once, it triggers the scenario for the random shutdowns. If you're having this issue, you can disable the driver, remove the NVRAM variables (NVRAM command)  and Network Profiles or plug in a Thunderbolt device to keep the driver happy. If you're having this issue and you've never plugged in a Network Adapter, think really hard. Did you lend it to someone or purchase it from someone who has? Did you take your MBP to an AppleStore or Service provider and had a diagnostics performed? The dongle they attached to your Thunderbolt port was an Ethernet Adapter."