Blue screen / stop code
Blue screen: INACCESSIBLE_BOOT_DEVICE
Windows could not read the drive it needs to start, cables, a new disk controller, BitLocker, or a failed drive.
What this error means
Windows started far enough to complain that the boot disk is missing or unreadable. Common after cloning a disk, changing SATA mode in firmware, adding a storage driver, or when the drive actually failed.
Common causes
- Storage driver or firmware (BIOS/UEFI) change
- Unseated drive cable or failed SSD
- BitLocker expecting a key
- A clone that did not copy the boot configuration correctly
Safe fixes
Think about what just changed
New SSD, new USB dock used as a boot device, firmware "optimized" to RAID, or a Windows update to storage drivers. If you can reach Automatic Repair, undo the last change rather than running every suggested fix.
BitLocker
If you enabled BitLocker, you may need the recovery key from your Microsoft account (only on accounts you control). Do not guess keys. Do not pay a stranger who claims they can "unlock" BitLocker without the key.
Advanced fixes
Hardware seating (desktops)
With the PC unplugged, a technician or a careful owner can reseat SATA or power cables. Laptops are not all user-serviceable. Do not force connectors.
When hardware may be involved
A drive that disappeared from firmware/BIOS is often dead or unplugged. Data recovery may still be possible; continued power cycles on a failing disk can reduce that chance.
When to get professional help
If this started after a shop cloned your disk, go back to them with the stop code. If it started with no hardware change, treat it as a possible drive failure and get help before a full format.