Quick fix: Boot to BIOS/UEFI (F2 or Del during power-on). Check that the SSD or HDD appears in the storage device list. If detected: verify Boot Order includes “Windows Boot Manager” or the drive itself. If not detected: reseat the M.2 stick or SATA cable, then re-check.

You power on the PC. Black screen with white text: “No boot device found,” “Boot Device Not Found,” or BIOS lists no drives. Three possibilities: (1) the drive is disconnected or failed, (2) the boot order doesn’t include the drive, or (3) the Windows boot configuration (BCD) on the drive is corrupted. Diagnose in that order.

Symptom: “No boot device found,” “Boot Device Not Found,” or similar at startup; Windows doesn’t load.
Affects: Windows 11 (and Windows 10) on any PC with SSD or HDD.
Fix time: ~30 minutes.

What causes this

The PC’s BIOS/UEFI reads the boot order list. For each entry, it tries to find a bootable signature. “No boot device found” means none of the listed devices contain a valid boot record. Three categories of cause: physical disconnection (loose cable, dead M.2 stick), boot order misconfigured (drive detected but not in boot list), or boot record corrupted (drive in list, but BCD is broken so BIOS can’t find boot manager).

Less commonly: a Windows update that mishandled UEFI boot entries, or BIOS settings that got reset by a CMOS battery failure.

Method 1: Verify drive is detected and in boot order

The first check.

Power off the PC fully. Wait 10 seconds.
Power on, immediately and repeatedly press the BIOS entry key. Common keys: F2 (Dell, ASUS), Del (most desktops), F12 (HP), F10 (some OEMs).
In BIOS, look for a Storage or Main section. Verify your SSD/HDD is listed by model name. Note its size.
If drive is not detected: power off, open the case (desktop) or service panel (laptop). Reseat the M.2 stick or unplug/replug the SATA cable. For laptops, reseat the M.2 by removing the retaining screw and re-inserting the stick.
If drive is detected in BIOS: navigate to Boot section. Look at Boot Order or Boot Priority list. Windows Boot Manager should be at the top. If not, move it up using F5/F6 or +/- keys.
For UEFI systems: ensure UEFI mode is enabled (not Legacy/CSM only). Boot → Boot Mode → UEFI.
Save BIOS settings (F10 typically) and reboot.
If Windows boots: you’re done. If still “No boot device,” proceed to Method 2.

This is the right first step. Solves 60% of cases.

Method 2: Rebuild the boot configuration from Windows USB

For when drive is detected and prioritized but Windows still doesn’t load.

Create a Windows 11 install USB from another PC using Media Creation Tool.
Boot the problem PC from USB. From the install screen: Repair your computer → Troubleshoot → Advanced options → Command Prompt.
Identify the Windows drive:
```
diskpart
list disk
select disk 0
list volume
```
Look for a volume labeled Windows. Note its letter.
Exit diskpart. Run the standard boot repair sequence:
```
bootrec /scanos
bootrec /fixmbr
bootrec /rebuildbcd
```
If bootrec /fixboot returns “Access denied” on UEFI systems: use bcdboot instead. Find the EFI System Partition and assign a letter (see “Where to Find the BCD File” article). Then: bcdboot C:\Windows /s S: /f UEFI.
For MBR/Legacy boot: also run bootsect /nt60 ALL to set the boot sector.
Remove USB. Reboot. Windows should boot.

This rebuilds the boot records when the drive is fine but BCD is broken.

Method 3: Address physical failure or BIOS reset

For when reseating doesn’t help.

Replace the CMOS battery if the PC is more than 4 years old. CR2032 coin cell, ~$2 at any electronics store. After replacement, BIOS settings reset to defaults — you need to re-configure boot order.
Test the SSD/HDD in another PC if possible. Use a USB-to-SATA adapter ($10) or M.2 enclosure. If the drive doesn’t mount on a known-good PC, it’s failed.
For desktops: try a different SATA port (port 1 may be primary; switching ports rules out a dead port). Try a different SATA cable.
For laptops: M.2 slots can fail. If the laptop has a second M.2 slot or a SATA bay, move the drive to test.
For PCs that detect the drive intermittently: check Event Viewer (if you can boot from a different drive) for drive errors. Failing SSDs often log errors before complete failure.
If the drive itself has failed and Windows is gone: data recovery may still be possible from a specialist (DriveSavers, Ontrack). For the boot drive replaced: install Windows fresh on the new drive, restore from backup.

This is the hardware-side path when software fixes don’t restore boot.

How to verify the fix worked

PC boots to Windows login screen without intervention.
Verify in BIOS: drive is listed by model, Boot Order shows Windows Boot Manager at top.
Once in Windows, open Disk Management. The system drive shows as Online — (System) (Boot) (Active) with healthy partitions.

If none of these work

If the drive is detected but Windows refuses to boot after BCD rebuild, deeper corruption is present. Run SFC and DISM: from WinRE Command Prompt, sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows and DISM /Image:C:\ /Cleanup-Image /RestoreHealth /Source:WIM:D:\sources\install.wim:1 /LimitAccess. Repairs system files. For Windows that lost its system partition entirely: diskpart → list volume. Look for an EFI System Partition (FAT32, ~100 MB). If missing, you’ll need to recreate it — this is involved; restore from backup is often faster. For PCs with BitLocker enabled: failed boot might prompt for recovery key. Get the key from account.microsoft.com/devices/recoverykey if your PC was linked to a Microsoft Account. Last resort — reinstall Windows: from the Windows 11 install USB, choose Install Windows. Pick the target drive. The installer can format and lay down a fresh install. Back up data first via WinRE Command Prompt (copy files to USB) since fresh install wipes the drive.

Bottom line: BIOS check first — drive detected? Boot order correct? If yes, rebuild BCD via Windows USB. If drive not detected, reseat hardware or test in another PC.