Chosen Solution
Having the same issue with my MacBook Pro retina 15" mid 2015 Turns off randomly - was brand new, from the box, on El Capitan which comes from the factory, downgraded to Yosemite and my MacBook Pro never had any issue again. only problem - have to use the Magic Mouse first edition, MM2 not compatible, which is annoying but less than the power issue hope someone will find it useful, happy macbooking
Sounds like you have a conflicting app or extension which is corrupting the systems memory. The fact that you down graded running the same apps tells me that. We have quite a few MacBook Pro’s of different series and we haven’t had any problems running OS-X El Capitan. MacOS Sierra has had some issues which I’m hoping this next update addresses. I would recommend you do a bit of house cleaning as storage space in the retina models can be an issue. Clear out the old cache & log files, here’s an app that makes quick work of it: Disk Doctor. Make sure you have 1/3 of the drive free if you have a 256 GB model, if you have a 512 GB or larger you only need to have 1/4 free.
