So guys I've been having this issue with my Macbook for almost a year and a half now. The thing randomly shuts down when it is not plugged in to a second screen, weirdly enough, it runs for days when I run it using Windows X. I've tried everything - wiping OS and installing new, checking to make sure everything is updated, turning off bluetooth, etc. etc. etc. About 2 years ago a beer was spillt on my computer, but this problem occurred a year after that so I don't know if its connected. I can run OS when the computer is plugged in to a second screen, I can run Windows X when it isn't plugged in, but for some reason it just keeps on turning off when it's running OS and not plugged in. Has anyone seen this before? Is there anything I can do?