I'm having a similar issue
System specs; Motherboard: ASUS Maximus VIII GENE, CPU: Intel 6700K (no overclocks), RAM: Crucial Ballistix Sport LT 32GB Kit (8GBx4) DDR4 2400
Storage: Samsung SM951 256GB AHCI,
GPU: EVGA 580 Classified PSU: EVGA Supernova 750 g2 OS: Windows 10 pro
Event Viewer message before each "Syestem shut down was unexpected" read:
"The description for Event ID 56 from source Application Popup cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer.
If the event originated on another computer, the display information had to be saved with the event.
The following information was included with the event:
ACPI
5
the message resource is present but the message is not found in the string/message table"
