Macbook pro mid 2014 15" turns screen off when unplugged and starts fans at max power I'm having a problem with my macbook where, for some reason, when it's unplugged to the power the computer randomly turns the screen semi-black (not totally black) and starts the fan at max power. 
The computer itself is still on (the apple is bright) and I have to turn it off by long pressing the power button.

I'm not able to understand what is going on:

The logs from system.log

Apr 19 09:15:03 marco com.apple.xpc.launchd[1] (com.apple.sandboxd[153]): Service exited due to SIGALRM | sent by kernel_task[0]
Apr 19 09:15:03 marco syslogd[96]: ASL Sender Statistics
Apr 19 09:15:05 marco com.apple.xpc.launchd[1] (com.apple.bsd.dirhelper[9925]): Endpoint has been activated through legacy launch(3) APIs. Please switch to XPC or bootstrap_check_in(): com.apple.bsd.dirhelper
Apr 19 09:15:05 marco systemstats[107]: assertion failed: 18D109: systemstats + 676139 [952918BC-3D73-37CE-8C6A-851AAF3C70D1]: 0x7f946c61bfe0
Apr 19 10:13:48 marco syslogd[96]: ASL Sender Statistics
Apr 19 10:13:48 marco com.apple.xpc.launchd[1] (com.apple.newsyslog): Service only ran for 8 seconds. Pushing respawn out by 2 seconds.
Apr 19 10:13:49 marco fud[9987]: objc[9987]: Class MobileAssetUpdater is implemented in both /System/Library/PrivateFrameworks/MobileAccessoryUpdater.framework/Support/fud (0x1029ab908) and /System/Library/AccessoryUpdaterBundles/ApplePowerAccessoryUpdater.bundle/Contents/MacOS/ApplePowerAccessoryUpdater (0x1054b2a68). One of the two will be used. Which one is undefined.
Apr 19 10:14:01 marco timed[133]: settimeofday({0x5cb98349,0xeea4a}) == 0
Apr 19 10:14:03 marco com.apple.xpc.launchd[1] (com.apple.duetknowledged[10064]): Could not find and/or execute program specified by service: 2: No such file or directory: /usr/local/libexec/duetknowledged
Apr 19 10:14:03 marco com.apple.xpc.launchd[1] (com.apple.duetknowledged[10064]): Service setup event to handle failure and will not launch until it fires.
Apr 19 10:14:03 marco com.apple.xpc.launchd[1] (com.apple.duetknowledged[10064]): Service exited with abnormal code: 78
Apr 19 10:20:55 localhost bootlog[0]: BOOT_TIME 1555662055 0


Where 10:15 is the computer still on, but close to the time of "death". I left it running from 10:15 to 10:20 (in this time the fan was running at fullpower) where I turned it off, but nothing appeared in the logs for that time period (weirdly)

Do you have any suggestion on how to debug and fix this issue? I might consider formatting everything as a last resort but I prefer not to because I have a lot of setup of various work projects

OSX Version: 10.14.3
If the screen is semi-black, it should change the brightness of the logo as well. Not sure how one is happening and the other is not.

Before you proceed, you might wanna take a backup of your data.

Do the below:


Reset NVRAM or PRAM on your Mac - https://support.apple.com/en-us/HT204063
How to reset the System Management Controller (SMC) on your Mac - https://support.apple.com/en-us/HT201295
Install Onyx and try to fix system issues - https://www.titanium-software.fr/en/onyx.html It's a powerful and reliable system maintenance app
If you are an advanced used, try live usb booting with Linux and see if the same problem happens. If it doesn't, then the problem is with macOS. You might need to format your mac. If it does, then you might have a hardware problem and should be handled in a different way.


Glad to be of help. Let me know how this goes.