Asus Laptop Boot Device Not Found — How to Fix

What Does This Error Mean?

Boot Device Not Found means the BIOS cannot find a drive with a valid OS. This is most often caused by a wrong boot mode, a corrupted boot record, or a failed/disconnected drive.

Affected Models

Asus ROG
Asus TUF Gaming
Asus VivoBook
Asus ZenBook
Asus ExpertBook

Common Causes

Hard drive failure or disconnection
BIOS Boot Mode mismatch (UEFI vs Legacy)
Corrupted Master Boot Record or EFI partition
Wrong boot order — USB or network listed first
Loose M.2 SSD connection

How to Fix It

Check if the drive is detected in BIOS.

Tap F2 at boot to enter Asus BIOS. Look in the storage section. If the drive is missing, the drive itself has failed or its connection is loose.
Verify Boot Mode and boot order.

Boot Mode should be UEFI for modern Windows. Windows Boot Manager should be first in the boot order. Reset BIOS defaults (F9) if you are unsure.
Repair the Windows boot record.

Boot from a Windows 10/11 installation USB. Select Repair > Troubleshoot > Command Prompt, then run: bootrec /fixmbr, bootrec /fixboot, bootrec /rebuildbcd
Reseat the M.2 SSD.

Power off and remove the bottom panel. Unscrew the M.2 SSD, remove and reseat firmly, then re-screw. M.2 drives can vibrate loose over time.
Replace the drive if not detected.

If the SSD is missing in BIOS even after reseating, it has failed. Replace with a compatible NVMe or SATA M.2 drive and reinstall Windows fresh.

When to Call a Professional

If the drive is detected in BIOS but Windows still will not boot after rebuilding the boot record, a technician can perform a fresh installation while preserving data.