MacBook Pro won't wake up sometimes Every once in a while when I plug in my MacBook Pro to my Thunderbolt Display and then press some keys on my external keyboard (laptop lid is closed) to wake it up, the computer won't wake up properly. The screen will either stay black or I will see a black screen and the beachball mouse cursor.

If I open the laptop lid in this situation nothing changes. If I then unplug the monitor nothing changes either. The laptop display is blank.

The only thing I can do at this point is to hold the power button until the machine turns off and then turn it back on.

This seems to happen about once or twice a week.

I'd rather not wipe the machine because it will take a while to reinstall everything.

Any ideas how to prevent this from happening?

Specs:


MacBook Pro (Retina, 15-inch, Mid 2015)
OS X El Capitan 10.11.6
For me upgrading to macOS Sierra resolved the issue. I tried resetting NVRAM and SMC but that didn't help.



Update 8/2/2018: turns out this issue is still happening to me now, just much less frequently, about once every few months.