Solve the Critical Error: Complete Troubleshooting Guide for "No Boot Device" on Windows PC/Laptop
The **"No Boot Device Found"** or **"No Bootable Device"** error is one of the most serious messages a Windows user can encounter. It means your computer cannot find the hard drive (HDD or SSD) containing the operating system, making it impossible to start Windows.
Don't panic! While this can indicate a hard drive failure, it is more often a fixable issue related to loose connections or incorrect BIOS settings. This comprehensive guide walks you through every step to diagnose and fix the **Windows No Boot Device Found** error.
📚 Table of Contents
- Phase 1: External & Connectivity Checks
- Phase 2: BIOS/UEFI Configuration
- Phase 3: Deep System Repair
- Phase 4: Diagnosing Hard Drive Failure
1. Phase 1: External & Connectivity Checks
Start with the simplest solutions. External devices and temporary settings can confuse the boot process.
| Action | How to Check/Fix | Why It Causes the Error |
|---|---|---|
| Disconnect External Devices | Unplug all USB drives, external hard drives, CDs/DVDs, SD cards, and docks. | If the BIOS is set to boot from external media first, and that media is non-bootable (or corrupted), the system won't look for the internal drive. |
| Hard Reboot | Hold the power button down for 10 seconds, then wait a few minutes and try starting normally. | Clears any temporary boot-time glitches and resets the connection between the motherboard and the drive. |
| Check Hardware Connections (Desktop Users) | If comfortable, open the PC case and ensure the SATA/Power cables to the HDD/SSD are securely fastened. | Loose or partially disconnected cables prevent the system from detecting the drive entirely. (Skip this step for Laptops unless performed by a professional.) |
2. Phase 2: BIOS/UEFI Configuration
Your BIOS (Basic Input/Output System) tells the computer where to find the operating system. Incorrect settings here are a very common cause of the "No Boot Device" error.
A. Access the BIOS/UEFI Menu
Restart your computer and immediately press the necessary key to enter the BIOS setup. (Common keys are **F2, F10, F12, Del**, or **Esc**).
B. Check Drive Detection
Once in the BIOS, navigate to the **Main** or **Storage** tab. Look for the list of connected SATA ports.
- Success: If your HDD/SSD is **listed here**, the drive is physically connected, and the problem is with the settings or boot data. Proceed to Step C.
- Failure: If your drive is **NOT listed**, the problem is likely a loose cable or hardware failure. (Go to Phase 4).
C. Correct the Boot Order
The system needs to know which drive to look at first.
- Navigate to the **Boot** tab.
- Ensure the first boot device is your hard drive (e.g., "Windows Boot Manager," "Internal Hard Drive," or the specific drive name like "Samsung SSD...").
- Save Changes and Exit (usually F10).
D. Check UEFI/Legacy Mode and Secure Boot
If you recently switched modes, Windows may stop loading.
- In the BIOS, check the **Boot** or **Security** section.
- If your Windows installation was originally set up with **Legacy** mode, ensure it stays that way. Switching to **UEFI** after installation will block the boot.
- Temporarily **disable Secure Boot** if it is enabled, then try booting again.
3. Phase 3: Deep System Repair
If the drive is detected in the BIOS but still won't boot, the boot configuration data (BCD) or Master Boot Record (MBR) is likely corrupted.
A. Use Windows Installation Media for Repair
You will need a bootable USB drive or DVD of the Windows version you have installed.
- Insert the installation media and boot from it (you may need to change the boot order again).
- Select your language, then choose **Repair your computer** (not Install Now).
- Go to **Troubleshoot > Advanced options > Startup Repair**.
- Windows will attempt to automatically repair the corrupt BCD or boot sector.
B. Manual BCD/MBR Repair (Command Prompt)
If the automatic repair fails, use the Command Prompt from the repair environment (Step A):
- Navigate to **Troubleshoot > Advanced options > Command Prompt**.
- Type the following commands, pressing Enter after each:
bootrec /fixmbrbootrec /fixbootbootrec /rebuildbcd
- Type
exitand restart the computer.
4. Phase 4: Diagnosing Hard Drive Failure
If your hard drive is **not detected in the BIOS** and the cable checks (for desktops) yielded no result, you are likely dealing with a physical hardware failure.
A. Run BIOS/UEFI Diagnostics
Many computer manufacturers (Dell, HP, Lenovo) include built-in diagnostics (sometimes accessible via **F12** or **F1** at startup) that can run tests on the hard drive. If this test fails, the drive must be replaced.
B. The Final Options
- Replace the Drive: The only solution for a failed drive is replacement. You will then need to perform a clean installation of Windows.
- Data Recovery: If the drive contains crucial, unbacked-up data, do not attempt further repairs. Take the drive to a professional data recovery service to avoid permanent loss.
Did the BIOS boot order change solve your "No Boot Device Found" error? Share which fix worked for you in the comments below!