How to Fix BOOT DEVICE NOT FOUND (Windows)
Quick Answer
The "BOOT DEVICE NOT FOUND" error indicates that your computer cannot locate a drive with an operating system to start from. This often occurs due to incorrect BIOS/UEFI boot order, a loose hard drive connection, or a corrupted boot sector. The fastest initial fix is to check physical connections and reset BIOS/UEFI settings to default.
What Causes This Error
- Incorrect boot order in BIOS/UEFI settings, causing the system to attempt booting from a non-bootable device.
- Loose or faulty hard drive/SSD connection cables (SATA data or power cables).
- Corrupted boot sector or Master Boot Record (MBR) on the primary boot drive.
- Hard drive/SSD failure or corruption, making the drive unreadable by the system.
- Operating system files are damaged or missing, preventing a successful boot.
- Incorrect or disabled boot mode (e.g., UEFI vs. Legacy) in BIOS/UEFI settings.
Step-by-Step Fixes
1Check Physical Drive Connections
- Shut down your computer completely and disconnect all power cables and peripheral devices.
- Open the computer case. For laptops, consult your manufacturer's manual for safe access to internal components.
- Locate the hard drive or SSD. Gently disconnect and then firmly re-connect the SATA data cable and power cable to both the drive and the motherboard.
- Ensure all RAM modules are seated correctly. If possible, reseat them.
- Close the computer case, reconnect power, and attempt to boot the system.
2Verify BIOS/UEFI Boot Order
- Restart your computer. As it starts, repeatedly press the designated key to enter BIOS/UEFI setup (commonly F2, F10, Del, or Esc).
- Navigate to the 'Boot' or 'Boot Order' section within the BIOS/UEFI utility.
- Ensure that your primary hard drive or SSD (where Windows is installed) is listed as the first boot device.
- If an external drive or USB is listed first and not intended for booting, move it down the priority list.
- Save changes and exit BIOS/UEFI. The system will restart.
3Restore BIOS/UEFI Default Settings
- Restart your computer and enter BIOS/UEFI setup using the appropriate key (e.g., F2, F10, Del).
- Locate the option to 'Load Default Settings,' 'Load Optimized Defaults,' or 'Reset to Default.' This option is often found on the 'Exit' tab.
- Select this option and confirm the action when prompted. This will revert all BIOS/UEFI settings to their factory defaults.
- Save changes and exit BIOS/UEFI. The system will restart with default settings applied.
4Run Windows Automatic Repair
- Insert your Windows installation media (USB drive or DVD) into the computer.
- Restart the computer and boot from the installation media. You may need to adjust the boot order in BIOS/UEFI to prioritize the media.
- On the 'Windows Setup' screen, select your language, time, and keyboard preferences, then click 'Next'.
- Click 'Repair your computer' in the bottom-left corner.
- Select 'Troubleshoot' > 'Advanced options' > 'Startup Repair'. Allow the repair process to complete and follow any on-screen instructions.
Advanced Fixes
Rebuild the Master Boot Record (MBR) or Boot Configuration Data (BCD)
- Boot your computer from Windows installation media as described in 'Run Windows Automatic Repair'.
- Navigate to 'Troubleshoot' > 'Advanced options' > 'Command Prompt'.
- In the Command Prompt, type 'bootrec /fixmbr' and press Enter.
- Next, type 'bootrec /fixboot' and press Enter.
- Then, type 'bootrec /rebuildbcd' and press Enter. If prompted to add installation to boot list, type 'Y' and press Enter.
- Type 'exit' and press Enter, then restart your computer.
Check Disk for Errors
- Boot your computer from Windows installation media and open Command Prompt as described in 'Rebuild the Master Boot Record (MBR) or Boot Configuration Data (BCD)'.
- Identify the drive letter of your Windows installation (it may not be C: in the recovery environment). You can usually find it by typing 'dir C:' then 'dir D:' etc., until you see Windows folders.
- Once you've identified the correct drive letter (e.g., D:), type 'chkdsk D: /f /r' and press Enter. Replace 'D:' with your Windows drive letter.
- Allow the disk check process to complete. This can take a significant amount of time depending on drive size and issues.
- Type 'exit' and press Enter, then restart your computer.
Frequently Asked Questions
What does 'BOOT DEVICE NOT FOUND' mean?
This error message indicates that your computer's BIOS/UEFI firmware cannot find a valid operating system to load from any of the connected storage devices. It means the system cannot initiate the boot process.
Can a loose cable cause 'BOOT DEVICE NOT FOUND'?
Yes, a loose or improperly connected SATA data cable or power cable to your hard drive or SSD is a common cause. The system cannot detect the drive if the connection is not secure.
Does this error mean my hard drive is broken?
Not necessarily. While a failing hard drive can cause this error, it can also be due to incorrect BIOS settings, corrupted boot files, or loose connections. It is important to troubleshoot other possibilities before concluding hardware failure.
How do I know if my hard drive is detected by the system?
You can check if your hard drive is detected by entering your computer's BIOS/UEFI settings. Look for sections like 'Storage,' 'Main,' or 'System Information' where connected SATA devices or drives are usually listed. If your drive is not listed there, it may not be detected.
What is the difference between BIOS and UEFI?
BIOS (Basic Input/Output System) and UEFI (Unified Extensible Firmware Interface) are both firmware interfaces that initialize hardware during the boot process. UEFI is a newer, more advanced standard that offers faster boot times, support for larger hard drives (GPT partitions), and enhanced security features compared to the older BIOS.