Windows Server 2019 reboot

The below is extremely thorough, however DISM may also be useful - 

    Open Start.
    Search for Command Prompt, right-click the top result, and select the Run as administrator option.
    Type the following command to perform an advanced DISM scan and press Enter: 
        DISM /Online /Cleanup-Image /ScanHealth
    Type the following command to repair the image and press Enter: 
        DISM /Online /Cleanup-Image /RestoreHealth

Booting from the ISO/DVD in recovery mode and swapping /Online for specifying the offline WIM may also be of some assistance, so did think to share :)

If your Windows Server 2019 is still rebooting unexpectedly despite:

Updated drivers

No issues from sfc /scannow

Clean memory diagnostics

Then it's likely a deeper hardware, software, or system configuration issue. Here's a detailed checklist to diagnose and resolve it:

Step 1: Check Event Viewer

Go to Event Viewer → Windows Logs → System or Application and look for:

Event ID 41 (Kernel-Power): Indicates an unexpected shutdown.

BugCheck: Related to Blue Screen errors.

Critical or Error logs around the reboot timestamp.

Look for patterns or repeating errors.

Step 2: Disable Automatic Restart on System Failure

This helps if the system reboots before showing a blue screen.

Run: sysdm.cpl → Advanced → Startup and Recovery → Uncheck "Automatically restart"

This may reveal a BSOD (Blue Screen) and error code

Step 3: Review Windows Update History

Check if a recent update or patch caused the issue.

You can roll back recent patches:

Settings → Update & Security → View update history → Uninstall updates

Step 4: Check for Driver Conflicts or Third-Party Apps

Use Reliability Monitor (perfmon /rel) to trace the crash.

Use Driver Verifier to stress test and catch faulty drivers:

Run verifier → Choose "Create standard settings" → Select all unsigned drivers.

If it crashes, note the .sys file involved.

Use with caution; this may trigger BSODs.

 Step 5: Power Supply and Hardware Check

Ensure the power supply is stable — use a UPS or test outlet.

Check for:

Overheating (CPU/GPU using tools like HWMonitor)

Bad disk sectors: Run chkdsk /f /r

Hardware failure (RAID controller, NIC, etc.)

Step 6: Run Dump Analysis

After BSOD, locate the minidump file in:

C:\Windows\Minidump\

Analyze with WinDbg or upload it here — I can help read it.

Step 7: Check Task Scheduler / Services

Ensure no task is forcing a shutdown/restart (rare, but possible).

Review Task Scheduler Library > Microsoft > Windows > UpdateOrchestrator or other scripts.

Step 8: Clean Boot

Try a clean boot to isolate third-party services:

msconfig → Services → Hide Microsoft services → Disable all

Startup tab → Disable all startup items

Restart and see if the issue persists.

Still Rebooting?

If all else fails, consider:

System Restore to a known good state

In-place upgrade/repair using Windows Server 2019 ISO

Full reinstall, if reproducible and unsolvable