Surface Pro 3 shuts down exactly every 30 minutes. Any ideas?

[MichelleOverhill]

Plugged in, not plugged in, doesn't matter. It's not overheating, not even warm. Battery life is still good. We've checked all the sleep settings, etc. Just started about a month ago.
Any ideas?

 

[sharpuser]

Might be a restart due to a (file) system failure.

Do a system file check (sfc)

1 - Open a DOS command window as administrator.
2 - Run this:
sfc /scannow

 

[GreyFox7]

This sounds vaguely reminiscent of what I heard in the past would happen if Windows was not licensed or activated. Check All Settings - Update & Security - Activation.

Did you reinstall the OS from a ISO? If so what version did you install?