Windows stopped with an INACCESSIBLE_BOOT_DEVICE bug check because it lost access to the system partition during startup. This usually points to storage-controller changes, disk failures, boot configuration issues, or a driver problem that prevents the boot volume from being mounted.
A storage controller, disk mode, or BIOS/UEFI setting changed and Windows no longer has the correct boot driver path.
The system disk or controller is failing, loose, or intermittently disconnecting during startup.
The boot file system could not mount the system partition because of corruption or an unsupported storage configuration.
A recent hardware or driver change introduced an incompatible disk, controller, or storage-driver dependency.
How to fix it
Reverse recent storage-related changes first, including BIOS/UEFI SATA mode changes, controller swaps, disk moves, or newly added storage hardware.
If Windows can still reach Safe Mode, boot into Safe Mode once and then reboot normally. This often reloads a core storage-driver path and restores normal startup.
Check storage hardware health and connection quality: reseat SATA/NVMe devices where applicable, inspect cables, and review SMART or manufacturer diagnostics for the system drive.
Run disk and boot troubleshooting from Windows Recovery or recovery media, including startup repair and a disk check if file-system corruption is suspected.
Update or roll back storage-controller and chipset drivers if the stop code began after a driver or firmware update.
If the system recently changed disk controller mode or boot hardware, restore the original configuration before attempting further recovery.
