Fix INACCESSIBLE_BOOT_DEVICE on Windows 10/11 (Exact Commands)

The fast answer. INACCESSIBLE_BOOT_DEVICE (stop code 0x7B) means Windows reached the disk but couldn't read the boot volume — almost always a wrong SATA mode (AHCI vs RAID), a missing storage driver, or a corrupted boot configuration after a bad update. If it started right after a Windows Update, boot into Windows Recovery (WinRE) and uninstall the latest update first. If not, fix the boot configuration from a Command Prompt in WinRE:

bootrec /scanos
bootrec /rebuildbcd
bootrec /fixmbr
bootrec /fixboot

Then reboot. If that fails, check the SATA mode in BIOS (AHCI vs RAID/IDE) — it must match what Windows was installed with.

Why this happens

Recent Windows Update — a cumulative update or driver update broke the boot path. This is the single most common cause.
SATA mode changed — the BIOS storage controller mode (AHCI, RAID, or IDE) was switched, or a CMOS reset reverted it. Windows can't load the disk with the wrong driver bound.
Missing storage driver — on RAID/VMD systems the storage controller driver (e.g. Intel RST / iaStorAC) isn't present in the Windows image.
Corrupted BCD or file system — an unclean shutdown damaged the boot configuration or the disk has bad sectors.

Step-by-step fix

Step 1 — Get into Windows Recovery (WinRE)

Force three failed boots (power on, then hold the power button to kill it as the Windows logo appears, three times) and Windows opens Automatic Repair. Or boot from a Windows 10/11 install USB and choose Repair your computer. Then go to Troubleshoot → Advanced options.

Step 2 — If it started after an update, uninstall the update

In Advanced options, choose Uninstall Updates → Uninstall latest quality update. This reverses most update-triggered cases without touching your data. Reboot and test before doing anything else.

Step 3 — Rebuild the boot configuration

In Advanced options → Command Prompt, run these in order:

bootrec /scanos
bootrec /rebuildbcd
bootrec /fixmbr
bootrec /fixboot

When bootrec /rebuildbcd finds a Windows installation, type Y to add it. Reboot and test.

UEFI/GPT note: on modern UEFI systems bootrec /fixboot can return "Access is denied" — that's normal and not the real fix on those machines. See the bcdboot procedure instead.

Step 4 — Check disk health

Still failing? Check the boot volume for file-system damage (replace C: with the Windows drive letter shown in WinRE):

chkdsk C: /f /r

Step 5 — Fix the SATA mode in BIOS

If the BSOD appeared after a BIOS reset or motherboard change, enter BIOS/UEFI setup (usually Del or F2 at power-on) and find the SATA Mode / Storage Configuration setting. Set it back to the mode Windows was installed with — usually AHCI on consumer PCs, or RAID/RST/VMD on systems that shipped that way. Save and reboot. Do not guess repeatedly; flipping it the wrong way just moves the error.

Step 6 — Inject the missing storage driver (RAID/VMD systems)

If the disk genuinely needs a driver Windows doesn't have, you can add it offline with DISM. You need the correct .inf driver for your controller on a second USB. C:\ is the offline Windows drive and D:\Drivers is the driver folder — confirm both letters in WinRE first:

dism /image:C:\ /add-driver /driver:D:\Drivers /recurse

Reboot and test. If you don't have the exact driver for your storage controller, stop here — loading a wrong driver can make boot worse.

Data safety: If the files on this machine matter and you don't have a backup, image the drive before you run repairs. chkdsk /r, BCD rebuilds, and SATA-mode changes are normally safe, but a drive that's already failing can lose data when stressed. Take a full sector image to a known-good external disk first, and never run repairs on the only copy of irreplaceable data.

GRAM tip: These steps run in Windows Recovery, which is already on the broken PC. Once the machine boots again, plug in GRAM — a free portable repair toolkit that runs from a USB inside Windows — to check the disk's SMART health and event logs, and let its AI agent confirm which root cause it was (SATA mode, driver, or bad update) so the stop code doesn't return.

Download GRAM free See AI pricing →

FAQ

Can I fix this without a second working computer?

Yes. You only need to reach Windows Recovery (WinRE), which lives on the broken PC itself — force three failed boots to trigger Automatic Repair, or boot from any Windows install USB. No second computer is required for the repair itself. (GRAM runs inside Windows rather than from boot media — use it once the machine boots to verify disk health and confirm the root cause.)

Will bootrec or chkdsk erase my files?

No. bootrec rewrites only the boot configuration, not your data. chkdsk /f /r repairs the file system and can occasionally move damaged file fragments to FOUND.000 folders, but it does not wipe the drive. If the data is irreplaceable, image the drive first anyway.

Should I set SATA mode to AHCI or RAID?

Match whatever Windows was originally installed with. Most consumer desktops and laptops use AHCI. Systems with Intel RST/VMD or a real RAID array use RAID mode. If you switch it and the error changes or persists, switch it back — don't leave it on a guess.

It only started after a Windows Update — what's the safest fix?

Uninstall the latest quality update from WinRE (Advanced options → Uninstall Updates). That reverses the change without touching your files and resolves most update-triggered INACCESSIBLE_BOOT_DEVICE cases. Re-apply updates later once the system is stable.