INACCESSIBLE_BOOT_DEVICEStop code 0x0000007B

What it means

INACCESSIBLE_BOOT_DEVICE, bug check 0x0000007B, means the kernel loaded far enough to need the boot drive and could not access it. The storage subsystem, the driver plus the firmware settings that let Windows talk to the controller, is the focus.

Most likely causes

• Storage-controller mode changed in firmware. Switching SATA mode between AHCI, RAID and IDE, or toggling NVMe/VMD options, after Windows was installed leaves Windows loading the wrong driver. See BIOS vs UEFI.
• A storage driver update or removal, sometimes as part of a Windows update.
• A cloned or migrated system where the boot configuration or driver does not match the new hardware or boot mode.
• Corrupted boot configuration data (BCD) or file-system damage on the system drive.
• A failing drive that intermittently disappears.

Fixes

1. Undo a recent firmware change. If you changed the SATA/NVMe mode, return it to its previous value. If unsure, try the other AHCI/RAID setting; the correct one lets Windows boot.

2. Uninstall a recent update or driver. From the recovery environment (interrupt boot three times): Troubleshoot → Advanced options → Uninstall Updates, or Startup Repair.

3. Repair boot data and the file system. In the recovery command prompt:

chkdsk C: /f /r
DISM /Image:C:\ /Cleanup-Image /RestoreHealth
bootrec /rebuildbcd

Adjust the drive letter to the offline Windows volume. See chkdsk and DISM.

4. Check the drive. If the above does not help, test the drive's SMART health and connections; an intermittently failing drive produces this and related file-system stop codes such as NTFS_FILE_SYSTEM.

General blue-screen approach

Most stop codes are caused by drivers, hardware faults, or corrupted system files, in that order of likelihood. The efficient path is:

1. Note what changed. A new driver, a Windows update, new hardware, or an overclock immediately before the crashes began is the prime suspect. Roll it back or remove it.
2. Boot to Safe Mode if Windows will not stay up: hold Shift and restart, or interrupt boot three times to reach the recovery environment, then Troubleshoot → Advanced options → Startup Settings → Safe Mode.
3. Update or roll back drivers, especially graphics, storage and chipset, from the vendor rather than only Windows Update.
4. Repair system files from an elevated prompt:

DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow

1. Test hardware: Windows Memory Diagnostic for RAM, the drive vendor's tool and chkdsk for storage, and check temperatures.
2. Read the dump. The minidump in C:\Windows\Minidump names the faulting driver when analysed with WinDbg or a tool like BlueScreenView.