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Windows

How to Fix INACCESSIBLE_BOOT_DEVICE Blue Screen (0x7B)

By Marcus Lee · About Zone Desire

Computer boot drive diagnostics and repair troubleshooting state
INACCESSIBLE_BOOT_DEVICE

Quick answer

INACCESSIBLE_BOOT_DEVICE (0x0000007B) means Windows lost access to the drive it boots from, often after a BIOS storage mode change, a failed update or a driver problem. Undo BIOS changes, use Startup Repair and uninstall the latest update from recovery.

What does “INACCESSIBLE_BOOT_DEVICE” mean?

During startup Windows could not read the system drive, so it could not load.

What causes it?

  • SATA mode changed in BIOS (AHCI/RAID/IDE)
  • Failed Windows update
  • Storage driver problem
  • Damaged boot files or drive

Steps to try

Stop when the issue is resolved.

  1. Undo any recent BIOS change, especially the SATA/storage mode.
  2. Let Windows fail to boot twice to open Automatic Repair, then choose Advanced options.
  3. Select Troubleshoot → Advanced options → Startup Repair.
  4. If it started after an update, choose Uninstall Updates → Uninstall latest quality update.
  5. Try System Restore from the same menu.
  6. If nothing works, check the drive connection or test the drive in another PC.

Need more support? Check the official help: Microsoft Support

FAQs

Will I lose my data?

Usually no. Startup Repair and uninstalling updates keep your files.

What is AHCI mode?

It is a storage controller setting in BIOS. Windows expects the same mode it was installed with.