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P2 · Windows Server

Windows 10/11 BSOD: INACCESSIBLE_BOOT_DEVICE (Stop Code 0x0000007B) During Boot

Windows 10/11 fails to boot and presents a blue/black screen with stop code INACCESSIBLE_BOOT_DEVICE (0x0000007B), indicating the OS cannot locate or access the boot drive. The error is most commonly triggered by an incorrect BIOS SATA mode setting (e.g., IDE or RAID instead of AHCI), corrupted Boot Configuration Data, a recently installed incompatible storage driver, or — after a disk clone or migration — stale BCD partition GUIDs, storage controller driver StartType misconfiguration in the cloned registry, or a missing/misconfigured EFI System Partition. Resolution involves correcting BIOS settings, running Startup Repair from WinRE, rebuilding the BCD with bootrec, repairing the EFI bootloader with bcdboot, fixing driver Start values in the offline registry, and — if Safe Mode is accessible — rolling back offending drivers or running System Restore.

Indicators

Likely causes

Diagnostic steps

  1. Restart the PC and enter BIOS/UEFI setup (typically F2, Del, or Esc during POST). Navigate to 'Advanced' or 'Storage' settings and confirm the SATA operation mode is set to AHCI. If it shows IDE or RAID, change it back to AHCI, save, and attempt a normal boot.
    Rules out BIOS SATA mode misconfiguration, the most common and quickest-to-fix cause of INACCESSIBLE_BOOT_DEVICE.
  2. If the SATA mode is already correct, boot from a Windows 10/11 installation USB. At the setup screen select 'Repair your computer' > 'Troubleshoot' > 'Advanced options' > 'Startup Repair' and allow the automated tool to detect and resolve boot issues.
    Automated Startup Repair resolves common BCD and bootloader issues without manual command-line intervention.
  3. If Startup Repair does not resolve the issue, open 'Command Prompt' from Advanced options and run the following commands in sequence to rebuild the BCD: 'bootrec /fixmbr', 'bootrec /fixboot', 'bootrec /scanos', 'bootrec /rebuildbcd'. Reboot after completion.
    Manually repairs MBR, boot sector, and rebuilds BCD when Startup Repair is insufficient.
  4. If the system still fails to boot normally, return to WinRE and navigate to Troubleshoot > Advanced options > Startup Settings > Restart. After the restart press the appropriate key to enter Safe Mode or Safe Mode with Networking to isolate driver or software conflicts.
    Safe Mode loads minimal drivers, allowing identification of driver-related causes without full system initialisation.
  5. If Safe Mode boots successfully, open Device Manager and Event Viewer. Identify any storage controller, NVMe, or chipset drivers installed or updated shortly before the error. Right-click the suspect device in Device Manager and choose 'Roll Back Driver' or 'Uninstall device', then reboot normally.
    Removes or reverts the specific driver responsible for the BSOD when a recent driver change is the cause.
  6. From Command Prompt in WinRE (or Safe Mode), run 'sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows' to scan and repair corrupted system files on the offline Windows 10/11 installation. Substitute the correct drive letter if Windows is not on C:.
    Repairs corrupted system files including storage subsystem components that may cause INACCESSIBLE_BOOT_DEVICE.
  7. If all preceding steps fail, use WinRE System Restore: Troubleshoot > Advanced options > System Restore. Select a restore point dated before the error first appeared and allow the rollback to complete, then reboot.
    Reverts the system to a known-good state when driver or update changes cannot be individually identified and reversed.
  8. From WinRE Command Prompt, run 'diskpart', then 'list disk' and 'list volume' to confirm the cloned disk is detected, identify its partition scheme (MBR/GPT), and verify the System Reserved or EFI System Partition is present and can be assigned a drive letter.
    Reveals firmware-level detection of the cloned disk and exposes partition layout issues (missing ESP, wrong scheme) that cause INACCESSIBLE_BOOT_DEVICE after cloning.
  9. Run 'bcdedit /enum all' from WinRE Command Prompt and inspect the 'device' and 'osdevice' entries to confirm they reference valid partition GUIDs on the cloned disk rather than stale identifiers from the source disk.
    Identifies stale BCD partition references — a primary cause of INACCESSIBLE_BOOT_DEVICE after disk cloning — that bootrec /rebuildbcd alone may not correct.
  10. Load the offline SYSTEM registry hive: 'reg load HKLM\OfflineSYSTEM D:\Windows\System32\config\SYSTEM' (adjust drive letter as needed). Check 'HKLM\OfflineSYSTEM\ControlSet001\Services\storahci' and '...\stornvme' Start values. A value of 3 or 4 means the driver will not load at boot. Set to 0 if incorrect: 'reg add HKLM\OfflineSYSTEM\ControlSet001\Services\storahci /v Start /t REG_DWORD /d 0 /f'. Repeat for stornvme if the target uses NVMe. Unload with 'reg unload HKLM\OfflineSYSTEM'.
    Corrects driver StartType misconfiguration in the cloned registry — the root cause when Windows cannot initialise the storage controller on dissimilar target hardware.
  11. For UEFI/GPT systems: in diskpart assign a letter to the EFI partition (e.g., 'assign letter=Z'), then run 'bcdboot C:\Windows /s Z: /f UEFI' to recreate the EFI bootloader. For MBR/Legacy systems: in diskpart, select the System Reserved partition and run 'active' to ensure it is flagged as the active boot partition.
    Repairs a missing or misconfigured bootloader on the cloned disk when the ESP was not cloned correctly or the active partition flag was lost.

Resolution path

Prevention

Tools

References

Windows 11Windows 10BSODINACCESSIBLE_BOOT_DEVICE0x0000007B0x7Bstop codeboot failureAHCISATA modeBCDbootrecWindows Recovery EnvironmentWinREStartup Repairstorage driverstorahci.syssfcSystem RestoreMBRboot sectordisk-clonemigrationbare-metal-restorestornvmeUEFIGPTdiskpartbcdeditbcdbootregistrydriver-starttypeEFIdissimilar-hardware