I just had the same issue. This is the 2nd time now.  All through alpha testing i never had this issue.  I was  in my ship  bridge  just idle.   I run Coretemp and MSI afterburner  and all temps are in optimal range.  I highly doubt this is a  temp issue.

It could be a invalid memory call or a forced reboot as some programs can call the system to do that directly.  I am not a programmer  but i have plenty of knowhow of  how PC's  work.

So, I stopped playing the game because of this crash after my last post just thinking I'll wait until game goes gold, maybe the problem won't persist.

It does.  

I cannot spend any length of time in between missions before the game SHUTS MY COMPUTER OFF.

I cannot reiterate this enough.  

THIS GAME SHUTS OFF MY COMPUTER.

This is rather hard to do without a heat issue.

This is NOT an overheat issue,  have verified this.

I wrote to support, @MEGAPULL‍ , sent my detailed specs and haven't heard anything back even after a follow up email was sent.

If you want my detailed specs, I suggest finding my email or requesting me to send it again personally. 

Hi! If you write a detailed email to the support team they will help you fix your problem. 

[email protected]

Finally completed opening missions on Martyr, thought problem solved, but no, starmap screen drops my machine as well.

Thought I saw something about a crash in starmap earlier but was unable to find that again.

Shuts off after ~5 minutes of being on the screen.  I found this useful bit in the logs:

The previous system shutdown at 8:45:47 PM on ‎4/‎21/‎2018 was unexpected.

I, however, did indeed expect it.

Didn't work for me.

Here are my specs:
     Time of this report: 4/20/2018, 19:25:03
             Machine name: hackblock-RN@7
               Machine Id: {the-smiling-bandit-strikes-again}
         Operating System: Windows 10 Home 64-bit (10.0, Build 16299) (16299.rs3_release.170928-1534)
                 Language: English (Regional Setting: English)
      System Manufacturer: ...
             System Model: Jugg-72
                     BIOS: 1.70
                Processor: AMD Ryzen 7 1700X Eight-Core Processor          (16 CPUs), ~3.4GHz
                   Memory: 16384MB RAM
      Available OS Memory: 16334MB RAM
                Page File: 7944MB used, 21701MB available
              Windows Dir: C:\Windows
          DirectX Version: DirectX 12
      DX Setup Parameters: Not found
         User DPI Setting: 96 DPI (100 percent)
       System DPI Setting: 96 DPI (100 percent)
          DWM DPI Scaling: Disabled
                 Miracast: Available, with HDCP
Microsoft Graphics Hybrid: Not Supported
           DxDiag Version: 10.00.16299.0015 64bit Unicode

Trying this from this post:

Steam Launch Parameters:

• Right click on Warhammer 40,000: Inquisitor - Martyr
• Click Properties>Set Launch Options
• Add: -single_core -forceservice -high  -LANPLAY -NOTEXTURESTREAMING
• You also need to set the Warhammer_x64_11.exe to run as admin.

I've been google-fu-ing this and haven't seen many folks with this specific issue; most have been ctds or things fixed by launching as admin, updating gfx drivers, the usual suspects.

Last events in the log:

    "@class":    ".LogEventRequest",
    "eventKey":    "inventoryUpdate",
    "data":    {
        "equipment":    [{
                "artifactId":    "5ad94bc3a281700504d83665",
                "set":    0,
                "slot":    "Armor"
            }, {
                "artifactId":    "5ad94bc3a281700504d83666",
                "set":    0,
                "slot":    "Wardrug"
            }, {
                "artifactId":    "5ad92d092f253c04fb3bd177",
                "set":    1,
                "slot":    "Mainhand"
            }, {
                "artifactId":    "",
                "set":    1,
                "slot":    "Offhand"
            }],
        "inventory":    [{
                "artifactId":    "5ad92d092f253c04fb3bd16f",
                "index":    0,
                "page":    2
            }, {
                "artifactId":    "5ad92d092f253c04fb3bd175",
                "index":    1,
                "page":    2
            }],
        "seen":    ["5ad94bc3a281700504d83664", "5ad94bc3a281700504d83666", "5ad94bc3a281700504d83665", "5ad94bc3a281700504d83663"]
    },
    "requestId":    "1524190271_45"
}
2018-04-19 22:11:11.205 (3741.907s) [            26C0]      SparksManager.cpp:313      0| WebSocket callback: {"@class":".LogEventResponse","requestId":"1524190271_45"}

I do not believe this is a heat issue, at least in my case; my computer's temp is well-regulated.

However, I get crashes that shut off my computer as well, usually at the mission select or inventory screen.  Note that this doesn't restart, it just clicks off as it would if you switched off your power supply.(edit: power supply is new and does not halt any other time IE other games, apps etc)

I do not see anything odd in the event viewer, no record of an application error.  I looked in the log and see a bunch of json-ey looking stuff and c++ references but nothing indicating an obvious error.  Anywhere else I could look?

If its restarting then it could be a Blue Screen of Death, which would point to a Hardware fault.

If its restarting then you need to set it to not restart on a crash and it will tell you whats wrong.

If its shutting down then you need to check the temps and test your power supply.