Fixes / Windows · Checked September 30, 2026

Windows Boot Device Not Found: what it means and how to fix it

Short answer

Boot Device Not Found means your PC's firmware (BIOS/UEFI) could not find a drive with a working Windows boot loader, so Windows never started. The most common fix is a hard reset: unplug the charger and all USB devices, hold the power button for 15 seconds, then start again. If that fails, load BIOS defaults and check the drive is first in boot order.

What this message means

This message comes from the computer's firmware (BIOS or UEFI), before Windows loads. At power-on, the firmware looks for a disk it can boot from. If it finds none, or finds a disk with no readable boot files, it stops and shows this screen. On HP laptops the full text is usually "Boot Device Not Found. Please install an operating system on your hard disk. Hard Disk (3F0)". Dell shows "No bootable device found". The cause can be a settings change (boot mode or storage mode), a loose or failing SSD or hard drive, or damaged Windows boot files. Your files are often still on the drive.

Common causes

Cause	How to tell
A static charge or temporary firmware glitch stops the drive from being detected	The error showed up suddenly after a normal shutdown, sleep, or battery drain. Nothing was changed, and the drive shows up again after a full power drain.
BIOS settings changed: boot mode switched to Legacy/CSM, boot order changed, or the SATA/storage mode changed after a BIOS update or CMOS reset	The drive appears in the BIOS storage or boot device list but isn't set to boot, or the error started right after a BIOS update, a dead CMOS battery, or someone changing BIOS settings. Windows 10 and 11 on modern PCs install in UEFI mode and won't boot from Legacy.
Loose, disconnected or failing SSD or hard drive	The drive is missing from the BIOS storage information page, the manufacturer's hardware diagnostics fail the drive test, or you hear clicking. It often comes after a drop, a repair, or several random crashes.
Corrupted Windows boot files (EFI partition, BCD or boot sector)	The drive shows up in BIOS and passes diagnostics, but the PC still won't boot. This often happens after a failed update, a power cut during an update, or disk partitioning or cloning.
A USB stick, SD card or external drive is set to boot first	The PC boots normally once you remove every USB storage device and memory card.

How to fix it

1. Do a hard reset and remove external devices

Shut the PC down. If it won't respond, hold the power button until it turns off.
Unplug the charger or power cable, then disconnect all USB drives, SD cards, docks and printers.
On laptops with a removable battery, take the battery out.
Hold the power button for 15 seconds to drain leftover charge.
Put the battery back, connect only the charger, and turn the PC on.

2. Load BIOS defaults and set the Windows drive as the first boot device

Keys vary by brand: HP uses F10 for BIOS setup and F9 to load defaults. Dell, Lenovo consumer, Acer and ASUS usually use F2 (some desktops use Del). Lenovo ThinkPad uses F1.

Turn the PC on and tap the BIOS key right away (for example F10 on HP or F2 on Dell).
Check that your SSD or hard drive appears on the storage or system information page. If it doesn't, skip to the diagnostics fix.
Load the default settings (on HP, press F9 and then Enter).
In the Boot menu, put Windows Boot Manager (or your internal drive) at the top of the boot order.
Save and exit (F10 on most PCs) and let the PC restart.

3. Switch boot mode back to UEFI and check the storage mode

Windows 10 and 11 installed on UEFI PCs. Setting names shown are Dell's; HP, Lenovo and ASUS use labels like Legacy Support, CSM, or Boot Mode.

Open BIOS setup (F2 at the Dell logo).
Set Boot Sequence or Boot Mode to UEFI instead of Legacy, and disable Legacy Option ROMs, CSM or Legacy Support.
For Windows 10 or 11, enable Secure Boot.
If the drive still isn't found, check SATA Operation (or Storage mode). Try the other option (AHCI or RAID On / Intel RST) and note which one you started with. Windows only boots in the mode it was installed with.
Save, restart, and change settings back if nothing improves.

4. Test the drive with the manufacturer's built-in diagnostics

HP: turn the PC on and tap Esc to open the Startup Menu, then press F2 for System Diagnostics. Choose Component Tests, then Storage (or Hard Drive), and run the quick test followed by the extensive test.
Dell: tap F12 at the Dell logo and choose Diagnostics (SupportAssist / ePSA).
Lenovo and other brands: use the diagnostics entry in the F12 or Novo boot menu, or the maker's UEFI diagnostics tool on a USB stick.
If the drive fails, or you get a failure ID, write it down. The drive needs to be replaced (it may be covered by warranty). Recover your data before anyone reinstalls Windows.

5. Run Startup Repair from Windows installation media

Windows 10 and Windows 11. You need a USB installer made on another PC with Microsoft's media creation tool, and your BitLocker recovery key if the drive is encrypted.

Plug in the Windows USB installer and boot from it using your PC's one-time boot menu (F9 on HP, F12 on Dell and Lenovo, Esc or F8 on ASUS).
On the Windows Setup screen, select Next, then Repair your computer.
Select Troubleshoot, then Advanced options, then Startup Repair.
When it finishes, remove the USB stick and restart.

6. Rebuild the boot files from Command Prompt

Windows 10 and Windows 11, only when the drive shows up in BIOS and passes diagnostics.

Boot from the Windows installation USB and press Shift+F10 to open Command Prompt (or go to Troubleshoot > Advanced options > Command Prompt).
Run bootrec /scanos and restart to see if that fixed it.
If it didn't, open Command Prompt again and run: bootrec /fixmbr, then bootrec /fixboot, then bootrec /rebuildbcd.
If bootrec /fixboot says "Access is denied" on a UEFI PC, you can rebuild the EFI boot files with bcdboot C:\Windows (check the Windows drive letter first with dir C:\ because it can differ in recovery).
Remove the USB stick and restart.

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Still not fixed?

If the drive is missing from BIOS even after a hard reset and loading defaults, or the manufacturer's diagnostics report a storage failure, the SSD or hard drive (or its connector) needs to be replaced. Contact the PC maker's support with the diagnostics failure ID. If the PC is under warranty, this is usually a covered repair. If you need your files, don't reinstall Windows or let anyone format the drive. A repair shop can often copy the data by connecting the drive to another computer, unless the drive has completely failed. If the drive passes every test and repair still fails, a clean install of Windows 10 or 11 from the media creation tool will fix corrupted boot files, but it wipes the drive, so back up first.

Questions people ask

Does Boot Device Not Found mean my hard drive is dead?

Not necessarily. Often it's a static charge, a BIOS setting or damaged boot files, and a hard reset or loading BIOS defaults fixes it. The drive is only likely to be failing if it's missing from BIOS or fails the built-in diagnostics test.

What does Hard Disk 3F0 mean on an HP laptop?

3F0 is HP's code for "no bootable device found". HP recommends a hard reset, loading BIOS defaults (F10, then F9, then F10 to save), updating the BIOS, and testing the drive with HP PC Hardware Diagnostics UEFI (Esc, then F2).

Will I lose my files fixing this error?

Hard reset, BIOS changes, Startup Repair and bootrec don't delete your files. Only reinstalling or resetting Windows, or formatting the drive, erases data.

Why did this appear after a BIOS or Windows update?

A BIOS update can reset boot mode, boot order or the SATA/RST storage mode, so the firmware no longer finds Windows Boot Manager. An interrupted Windows update can also damage boot files, which Startup Repair or bootrec can fix.

Should I switch my BIOS to Legacy mode to fix it?

No, not for Windows 10 or 11 installed in UEFI mode, because Legacy mode causes this error on those PCs. Dell notes that a system installed in Legacy mode can't be fixed by switching to UEFI and needs Windows reinstalled.

Sources

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