How to Fix “Boot Device Not Found” Error Without Data Loss

“Boot Device Not Found” means the computer cannot find a usable internal SSD or hard drive, or cannot find the files needed to start Windows. Check BIOS/UEFI first: if the drive is missing, investigate connections or hardware; if it is listed, correct the boot order or repair Windows startup. Do not reinstall Windows or format the drive until you know it is healthy and your data is backed up.

What does “Boot Device Not Found” mean, and is your drive still visible?

The message appears before Windows loads, while the computer’s firmware is looking for a bootable device. Firmware may fail to find the physical SSD or hard drive, or it may detect the drive but fail to find a valid Windows boot entry.

Boot Device Not Found

The distinction determines what to do next. A drive that is absent from BIOS or UEFI may be disconnected, disabled, incompatible with the current storage setting, or failing. Windows repair tools cannot repair a drive that the firmware does not detect.

A drive that appears in firmware but does not start Windows usually points to the wrong boot order, a damaged EFI boot entry, corrupted boot files, or a recent update that did not complete correctly.

Use this quick check:

• If BIOS/UEFI lists the internal SSD or hard drive by model name, continue with the boot-order check.
• If BIOS/UEFI lists Windows Boot Manager, that is normally the preferred boot option for a Windows installation using UEFI.
• If neither the drive nor Windows Boot Manager appears, shut the computer down and investigate connections and hardware before attempting Windows repair.
• If the drive appears intermittently, makes unusual sounds, or the computer recently froze or crashed, prioritize data recovery rather than repeated startup attempts.

Firmware detection only proves that the computer can communicate with the drive. It does not prove that your files or Windows installation are intact.

Before changing anything, check these simple causes

These steps apply to Windows 10 and Windows 11 computers, including many laptops and desktops from major manufacturers. They do not require Administrator access. A restart may be necessary, but these checks should not erase files.

Before opening a computer or changing firmware settings, remove external storage and record what happened immediately before the error. If important files are not backed up and the drive shows warning signs, prioritize backup or data recovery before repeated restarts.

1. Remove USB flash drives, external hard drives, memory cards, phones, and other storage devices. A computer can sometimes try to boot from removable media instead of the internal drive.
2. Power the computer off completely. Hold the power button only if it will not shut down normally, then disconnect the charger or power cable. On a desktop, switch off the power supply if needed. Wait briefly, reconnect power, and start it again.
3. Record what happened immediately before the error. An interrupted update, a drop, a repair, a newly installed drive, or a BIOS change can point to different causes. If the problem began after a BIOS change, the storage controller mode or boot mode may have changed.
4. If you have a desktop and are comfortable opening it, turn it off and disconnect power before checking the internal drive connections. Reseat the SATA data cable and power cable, or remove and reinstall an M.2 SSD according to the computer or motherboard instructions. Do not force a connector.
5. Try the manufacturer’s one-time boot menu, commonly opened with a key such as F12, Esc, or another key shown on screen. If the internal drive or Windows Boot Manager appears there, the drive is at least being detected at that stage.

If reseating a connection makes the drive reappear, copy important files as soon as Windows starts. An intermittent connection or drive can also be an early sign of hardware trouble.

How to check BIOS or UEFI and choose the correct boot drive

BIOS and UEFI settings are opened before Windows starts. Administrator access is not required. The key varies by manufacturer; common choices include F2, Delete, Esc, or F10. Start the computer and press the indicated setup key repeatedly as soon as it powers on.

Firmware setup > Storage, System Information, or Main > Boot

Look for the internal SSD or hard drive under storage information. It may be shown by a model number rather than by the word “Windows.” Then open the boot-order page.

1. Confirm that the internal drive is listed under storage information.
2. If Windows Boot Manager is listed for the correct internal drive, move it to the first boot position. On some systems, you select it and use an on-screen key such as +, -, or a function key.
3. If Windows Boot Manager is not listed but the internal drive is visible, select the internal drive as the first boot device. This may allow the firmware to find the boot files directly, though a missing Windows entry may still require repair.
4. Save the change using the firmware’s Save and Exit option, then allow the computer to restart.

The expected result is that Windows starts normally or displays a Windows recovery screen instead of the original firmware error. If the drive is listed but the error returns, the boot entry or Windows startup files may be damaged.

Avoid changing Secure Boot, CSM or Legacy Boot, RAID mode, and AHCI mode just to test them. Those settings affect how the system starts or communicates with storage. Changing one without knowing its previous value can create another boot problem. If a BIOS reset caused the error, restore the documented original boot mode and storage-controller mode rather than guessing.

If the drive is not listed anywhere in firmware, changing the boot order will not fix it. Move to hardware diagnostics and data-recovery decisions instead.

Run hardware diagnostics before repairing Windows

Most computer manufacturers include a storage test in their preboot diagnostics. Administrator access is not required. Open it from the startup diagnostics key or from the firmware menu; the exact key and menu name vary by manufacturer.

Startup diagnostics > Storage test, Drive test, or SSD test

1. Run the short test first.
2. If it passes and the problem remains, run the extended test if one is available.
3. Record any error code or drive identifier before exiting.

A passing test and a consistently detected drive support continuing with Windows startup repair. If the test fails, the drive disappears from firmware, or the computer reports a SMART warning, stop trying random boot repairs.

Treat these signs as warnings:

• Clicking, grinding, or repeated spin-up sounds from a mechanical hard drive.
• Frequent freezes, blue-screen errors, corrupted files, or sudden restarts before the boot failure.
• A drive that appears only occasionally or vanishes after warming up.
• A SMART warning or a failed manufacturer diagnostic.
• An SSD that is missing from BIOS/UEFI after its connections have been checked.

Copying files from a failing drive can become harder if the drive deteriorates. If the data matters, use another computer or a reputable data-recovery service, and avoid formatting, initializing, or repeatedly powering a failing drive on and off.

A drive that passes a basic test can still have corrupted files or developing faults. If Windows eventually starts, back up important files immediately before continuing. If the drive is under warranty, keep the diagnostic result and contact the manufacturer. Replacement is usually safer than continuing to use a drive that fails its hardware test.

If the drive is detected but Windows still will not start

Only use Windows startup repair after BIOS/UEFI consistently detects the internal drive and hardware diagnostics do not indicate a failure. You may need a Windows recovery environment from the computer’s built-in recovery tools or a Windows installation USB. These recovery options generally do not require an Administrator account at the initial menu, but a recovery command prompt may ask you to select an account and enter its password.

If the problem began after an update

Open Windows Recovery Environment and try the least disruptive option first:

Troubleshoot > Advanced options > Uninstall Updates > Uninstall latest quality update

If the failure followed a larger version upgrade, the recovery menu may also offer Uninstall latest feature update. Restart after the removal. If the update cannot be removed or the option is unavailable, try System Restore if a restore point exists.

If Windows starts after the update is removed, the update was likely involved. If the error remains, return to the recovery options rather than repeatedly changing BIOS settings.

If boot files or startup configuration are damaged

From the same recovery environment, run Startup Repair first:

Troubleshoot > Advanced options > Startup Repair

Let it complete and restart once. The expected result is a normal Windows boot. If it reports that it could not repair the computer, use Advanced options > Command Prompt only if you are comfortable identifying the Windows and EFI partitions. Drive letters in recovery mode may differ from those used in normal Windows.

For a UEFI Windows installation, the following pattern can rebuild the boot files after you have identified the correct Windows partition and EFI partition. The drive letters shown are examples and must not be copied blindly.

diskpart
list volume
exit
bcdboot D:\Windows /s S: /f UEFI

The expected result is a message that the boot files were successfully created. If D:\Windows does not contain the Windows folder, or S: is not the small EFI system partition formatted as FAT32, stop and identify the partitions rather than trying random letters. Do not use diskpart clean, format, or delete partitions as a repair experiment.

If the command succeeds but Windows still does not start, the problem may involve another startup component, the Windows installation, or the drive itself. Return to hardware checks before using more invasive options.

If the drive must be replaced

If diagnostics fail, the drive is not detected, or it has become unreliable, replace the drive before reinstalling Windows. If the old drive is still readable, recover or clone the data first; cloning a failing drive may require specialized software or hardware. After installing a healthy drive, reinstall Windows from official installation media and restore your files from a backup.

If there is no backup and the old drive contains irreplaceable data, seek recovery help before replacing or modifying it.

A successful startup repair should lead to the Windows sign-in screen without the firmware error. Once Windows loads, confirm that your files open, check the drive’s health with the manufacturer’s utility, and create a current backup.

Conclusion

Check BIOS/UEFI and the manufacturer’s storage diagnostics before repairing Windows. If the drive is missing, unreliable, or failing, protect the data and plan for recovery or replacement; if it is detected and healthy, set `Windows Boot Manager` first and use the appropriate Windows recovery option.

Frequently Asked Questions

Can a BIOS update cause a “Boot Device Not Found” error?

Yes. A BIOS update or reset can change the boot mode, storage-controller mode, or boot order. Check whether the internal drive and `Windows Boot Manager` are visible, then restore the documented settings for that computer. Avoid changing several firmware settings at once.

Will Startup Repair delete my personal files?

Startup Repair is designed to repair startup components without deleting personal files, but no repair process is risk-free if the drive is failing. If Windows Recovery can access the drive and your files are not backed up, consider copying important data before using more invasive options.

What if the SSD is visible in BIOS but not in Windows Recovery?

Check the recovery environment’s disk and partition listings, because drive letters can change there. If the disk is absent from both firmware and recovery tools, suspect a connection or hardware problem. If it appears but has damaged partitions or unreadable data, stop before formatting and prioritize recovery.