INACCESSIBLE BOOT DEVICE

Question

INACCESSIBLE BOOT DEVICE

Answer 1

Hi,

If it's a laptop or desktop, if possible, could you provide the laptop model or your desktop configuration?

Can you access the BIOS, go to the Boot tab, take a picture and post it here?

Thanks

Answer 2

The INACCESSIBLE_BOOT_DEVICE stop error (0x7B) indicates Windows can’t access the system disk during startup. It’s usually caused by storage driver or controller changes, disk/partition corruption, or hardware problems.

Follow these steps to troubleshoot.

1. Revert recent hardware/firmware changes

• If any storage-related hardware was recently added or changed (disk, SSD, SATA/NVMe controller, external enclosure), remove or revert it and try booting again.
• If UEFI/BIOS settings were changed (for example, controller mode switched between IDE/RAID/AHCI), revert those changes.
• If the issue started after repartitioning the system disk or changing boot order, undo those changes if possible.

2. Try automatic repair / WinRE If Windows can’t boot normally, enter Windows Recovery Environment (WinRE):

• Boot from Windows installation media for the same Windows version.
• On the Install Windows screen, select Next > Repair your computer.
• Go to Troubleshoot and try Startup Repair first.

If Startup Repair doesn’t fix it, open Command Prompt from WinRE and continue.

3. Verify the disk is visible and the OS volume exists At the WinRE Command Prompt:
4. Run:

      diskpart
      list disk
   

   Confirm the system disk is listed and shows as Online.
5. Then run:

      list vol
   

   Ensure the volume that contains Windows and the boot (SYSTEM) partition are present.
   • If the OS disk or volumes are missing, this indicates a hardware or virtualization issue; contact the OEM or virtualization provider.
6. Check Boot Configuration Database (BCD) Still in WinRE Command Prompt, run:

bcdedit

Verify in the Windows Boot Manager and Windows Boot Loader sections that:

• device and path entries point to the correct system partition and boot loader file. If entries are wrong or missing, repair BCD using standard bootrec/bcdboot procedures appropriate for the system layout.

5. Check for storage compatibility and firmware Once the system can boot or from another machine:

• Confirm disk controllers and storage drivers are compatible with the installed Windows version.
• Update UEFI/BIOS and storage controller firmware to the latest versions.

6. If Windows can boot intermittently After getting back into Windows at least once:
7. Ensure there is sufficient free disk space (ideally 10–15% free) on the system drive.
8. Open Device Manager and look for devices with an exclamation mark. For any storage-related device with issues, review the driver events and update or roll back the driver.
9. Check Event Viewer → System log for critical errors around the time of the blue screen to identify failing devices or drivers.
10. Run hardware diagnostics provided by the system manufacturer to check for disk or controller failure.
11. Run System File Checker from an elevated Command Prompt:

        sfc /scannow
    

    This repairs missing or corrupted system files.
12. If the error started after a recent driver/app/update installation, use System Restore from Troubleshoot → Advanced options → System Restore in WinRE to revert to a restore point from before the issue.
13. If the VM scenario applies (Azure) If this is an Azure Windows VM and it shows INACCESSIBLE_BOOT_DEVICE or “Boot failure”:

• First stop (de-allocate) and then start the VM again and check if it boots.
• If it still fails, investigate BCD corruption or inactive system partition as described for Azure VMs.

If none of these steps restore bootability and the disk is visible, the remaining options are advanced debugging with a kernel debugger or full OS reinstallation, ideally after backing up data from the disk using another system.

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References:

• Bug check 0x7B: INACCESSIBLE_BOOT_DEVICE
• Advanced troubleshooting for Stop error 7B or Inaccessible_Boot_Device
• Windows boot error INACCESSIBLE_BOOT_DEVICE in an Azure VM
• How to recover devices from an unbootable state after installing the January 2018 security update