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0x0000007BINACCESSIBLE_BOOT_DEVICEStop codeWidely reported

INACCESSIBLE_BOOT_DEVICE (0x7B): what it means and how to fix it

Updated Oct 2, 2026 · Checked against Microsoft documentation · How this page is made

Quick answer

This error means Windows lost connection to the drive containing your operating system during startup. It is most often caused by recent hardware changes, corrupted system files, or an interrupted Windows update. Start by checking your BIOS settings or reverting any recent hardware additions.

What it means

What this error means

When you turn on your computer, Windows must load its core files from your hard drive or SSD. The INACCESSIBLE_BOOT_DEVICE error occurs when Windows starts the boot process but cannot find or communicate with the storage device where it is installed. Because the operating system cannot load the necessary drivers to read the drive, it stops immediately to prevent data corruption, resulting in a blue screen.

Why it happens

This error usually appears after a specific change to your system. Common triggers include changing storage settings in your BIOS (such as switching between AHCI and IDE modes), installing a new hard drive or controller, or a failed Windows update that left system files in an inconsistent state. It can also occur if the boot configuration files, which tell the computer where to find Windows, have become corrupted or if the storage hardware itself has developed a physical fault.

Common causes

  • Recent changes to BIOS or UEFI storage controller settings.
  • Corrupted system files or boot configuration data.
  • A failed or interrupted Windows update process.
  • Physically faulty hard drive or storage controller hardware.
  • Incompatible or missing drivers for the storage controller.

How to fix it

Safest and most likely fixes first. Readers' answers to "Did this fix it?" reorder this list over time.

  1. Revert recent hardware and BIOS changes

    Use this if you recently added new hardware or changed settings in your BIOS/UEFI menu.

    1. Disconnect any recently added hard drives or external storage devices.
    2. Enter your BIOS/UEFI setup menu during startup (usually by pressing Del, F2, F10, or Esc).
    3. Check if the storage controller mode (often labeled as SATA mode or AHCI/IDE) was changed and revert it to the previous setting.
    4. Save your changes and exit to see if the system boots normally.
    Did this fix it?

  2. Boot into Safe Mode

    Use this if you can access the Windows recovery environment to see if the system can load with a minimal set of drivers.

    1. Restart your computer and enter the Windows Recovery Environment (WinRE).
    2. Select Troubleshoot, then Advanced options, then Startup Settings.
    3. Select Restart.
    4. After the computer restarts, press 4, 5, or 6 to enter Safe Mode.
    5. If Windows loads, restart your computer normally to see if the storage drivers initialize correctly.
    Did this fix it?

  3. Run System File Checker

    Use this if you suspect corrupted system files are preventing the boot process.

    1. Boot into the Windows Recovery Environment using installation media.
    2. Select Repair your computer, then Troubleshoot, then Command Prompt.
    3. Type sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows and press Enter (replace C: with your actual OS drive letter if different).
    4. Wait for the process to complete and restart your computer.
    Did this fix it?

  4. Rebuild the Boot Configuration Data

    Use this if the error persists and you suspect the boot files are damaged.

    1. Open the Command Prompt from the Windows Recovery Environment.
    2. Type bootrec /rebuildbcd and press Enter.
    3. If the command finds a Windows installation, follow the on-screen prompts to add it to the boot list.
    4. Restart your computer.
    Did this fix it?

Is it just you?

25+ Microsoft Q&A threads discuss this. Most recent activity:

Checked Oct 2, 2026. Refreshed automatically every few days.

Sources

Frequently asked questions

Can a Windows update cause INACCESSIBLE_BOOT_DEVICE?

Yes, if an update is interrupted or fails to commit changes to the system files, it can leave the boot configuration in a state that Windows cannot read.

Is my hard drive dead if I see this error?

Not necessarily, though it is a possibility. This error is often caused by software configuration issues or driver conflicts rather than physical hardware failure.

How do I fix this if I cannot get into Windows?

You will need to use a Windows installation USB drive to access the recovery tools or Command Prompt to perform repairs like running the system file checker or rebuilding the boot configuration.

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