This is my first question on this forum. My MacBook has been turning off randomly when left unplugged. It shuts down before the battery indicator reaches 0%. I have reset the SMC and PRAM several times before. It starts up and i've cycled the battery 2 or 3 times after a reset. So it does start up without being connected and has let me cycle the battery from 100% to 0% Since it's actually letting me cycle the battery, i'm under the impression that it's working again. But out of no where it's shuts off on me randomly.

I thought maybe it could be the thermal paste on the heatsink just getting old, but why doesn't it shut down when connected to power? Could the battery be bad? The indicator is showing that it has charge. Could it be possible that the SMC chip has gone bad? I have had this MacBook since 2012. I've put some work into it. Increasing the RAM, replacing the optical drive with an SSD, reapplication of thermal paste to both the CPU and GPU. Could it be a one of my hardware monitoring programs forcing a shut down? I get no warning prior to the machine turning off. I can start it right back up after but it isn't log before it does it again. The more I start it up after the shut down, the less time it takes to shut down again the next time.

MacBook info:

  • MacBook Pro (15-inch, Mid 2012, Unibody)
  • 2.6 GHz Intel Core i7 processor
  • 16GB 1600 MHz DDR3 RAM
  • NVIDIA GeForce GT 650M 1 GB / Intel HD Graphics 4000 1536 MB
  • 500GB SSD
  • 1TB HDD


I used different battery health apps and they show that my battery is good. Using the system_profiler SPPowerDataType command showed that the amperage was zero which according to the Fully charged MacBook Air turns off when power cord removed post meant that the battery is bad. I'm guessing this doesn't alway prove to be true, at least not in my case. I am currently running my MacBook without the charger plugged in and it isn't shutting down right away after unplugging it.

  • Is there any message when it turns back on? When did this start occurring? Was this shortly after installing some new hardware? Can you run an Apple Hardware Test? support.apple.com/en-us/HT201257 – JBis Apr 8 '18 at 23:57
  • No message when turned back on. This started occurring shortly after streaming to my Chromecast one time. I use HWMonitor, and as i was streaming i got a bunch of warnings that my GPU was overheating. I immediately stopped streaming and never tried again. About 2 days after is when my MacBook started with this issue. I had not installed any new hardware recently. I will run a hardware test just incase and update you. Thanks for that suggestion. – Ryan Luna Apr 9 '18 at 0:33
  • AHT does not work on my mac i get a DEC400 error – Ryan Luna Apr 9 '18 at 17:37
  • It looks like that’s your issue. Research the error code. – JBis Apr 10 '18 at 10:46