What to do when boot device failed?

A boot device failure can be incredibly frustrating. When you press the power button on your computer and it won’t boot up, it’s not only annoying, but can also make you feel powerless. The good news is that while a failed boot device may seem like a catastrophic problem, there are some troubleshooting steps you can take to resolve the issue yourself.

1. What does “boot device not found” mean?

The “boot device not found” error essentially means that your computer is unable to find the system boot device it needs to start up. This is usually the primary hard drive where the operating system is installed. When this error appears, your computer will not be able to load Windows or any other OS installed on that hard drive.

Some common reasons why this error may show up include:

  • The boot order is incorrect in the BIOS settings
  • The hard drive with the OS installed has failed or become corrupted
  • The hard drive connection has become loose
  • An update or change has altered required boot files

Figuring out the specific reason will inform how you can resolve the boot device not found issue.

2. Try restarting your computer

The first step whenever you encounter any kind of error message or odd system behavior is to simply restart your machine. Completely power down the system and unplug it from power for 30 seconds. This resets various components and memory caches that could potentially be contributing to boot issues.

Restart and see if the “boot device not found” error still appears when you power the computer back on. If the restart resolved it, you likely were dealing with a minor software glitch or memory issue that a reboot cleared up. No further action should be needed in that case.

3. Check your BIOS settings

If restarting didn’t fix the problem, the next place to check is your system BIOS settings. Access the BIOS setup utility by pressing a key like F2, F10 or Delete during the initial boot-up sequence. This gets you into the pre-boot environment before the OS loads.

Look for the boot order configuration and ensure the hard drive or SSD where your operating system is installed is listed as the first boot device priority. If the drive with the OS is not at the top of the boot order, the system will attempt to boot from another device first, resulting in the error.

While here in the BIOS, also check that the SATA operation mode is set to AHCI rather than IDE if you are using an HDD. AHCI mode is required for modern OS installations.

4. Open the case and check connections

Connections coming loose inside your PC case can also produce the boot device error. Power down your system fully, unplug the power cable, and open up the case to get access to the motherboard.

Check that both the power and SATA data cables are securely attached to the hard drive. Reseat each cable firmly into the drive to ensure a tight connection. Also verify the other end of each cable is properly connected to the power supply and motherboard SATA port respectively.

If you have an M.2 SSD installed directly on the motherboard, ensure it is seated in the slot completely flush with the bottom and is screwed in fully. A loose M.2 drive can easily fail to boot.

5. Test your RAM

Faulty RAM sticks can also prevent system boot and lead to the boot device error. Remove all but one RAM module from your motherboard and attempt to boot the computer. If it still fails, swap in a different stick and try booting with each one individually. If the system successfully boots with one RAM stick, you have found your bad module.

You can also perform extensive RAM testing and diagnosis using a bootable USB tool like MemTest86. This comprehensive memory check will detect any flaws or errors in your installed RAM.

6. Try booting from a USB drive

See if you can boot the computer from an external USB stick or drive. Download a bootable operating system installer or diagnostic tool like UBCD and create a bootable USB drive. Connect that drive to your PC and configure it as the first boot device in BIOS.

If your system boots from the USB properly, that indicates your main boot hard drive is likely failed or corrupted. However, if it still fails to boot, the issue lies with the motherboard or components.

7. Remove recently added hardware

New hardware you recently installed could potentially be the source of the boot failure. If you added any new drives, cards, memory or other components right before the “boot device not found” errors began, try removing that new hardware and see if it boots normally again.

Recently installed PCIe cards in particular can throw off the boot process if they are not fully compatible with your motherboard or BIOS version. Swap out for a different GPU, WiFi or capture card if issues started after installing it.

8. Reset BIOS to default settings

Resetting your motherboard BIOS settings to their factory defaults can fix boot issues caused by an incorrect or outdated configuration. Consult your motherboard manual for the jumper pins that need to be shorted to clear the CMOS. Alternatively, removing the CMOS battery for a couple minutes will wipe the existing BIOS settings.

After resetting BIOS, be sure to go back in and reorder your boot sequence and reconfigure any other necessary options like XMP memory profiles or fan curves.

9. Check for drive errors using CHKDSK

Using the CHKDSK utility, you can scan your boot drive for any filesystem errors or bad sectors that could be preventing it from booting properly. CHKDSK will attempt to repair any damage found.

Boot from a Windows recovery drive or installation media in repair mode to access the Command Prompt. Run “chkdsk C: /f” to perform a full check and repair on your C: drive. If any corruption is found, reboot and see if the boot error now clears.

10. Reseat and check your CPU

While less common than drive or memory issues, a loose or incompatible CPU can also be the hidden cause of the boot device error in some cases. Open up your case again and locate the CPU socket on the motherboard.

Carefully release the retention arm lever and reseat the processor chip, ensuring it is fully inserted into the socket pins. Lock the retention arm back down firmly. Also verify the CPU power connections are plugged in properly near the socket before reassembling your system.

Make sure your motherboard BIOS is updated to the latest available version that supports your specific installed CPU as well. An outdated BIOS may fail to recognize the processor.

11. Replace the CMOS battery

The small CMOS battery on your motherboard provides power to store BIOS settings when the system is powered off. If this battery dies, it can cause boot issues and the “boot device not found” error.

Locate the flat silver battery near the BIOS chip and pop it out of the holder. Replace it with a brand new CR2032 3-volt coin cell battery. This should only cost a few dollars at any electronics or hardware retailer. Installing a fresh CMOS battery will restore stable power to BIOS.

12. Update BIOS and firmware

An outdated version of your motherboard’s BIOS firmware is another possibility with this boot error. Locate and install the latest BIOS update for your specific motherboard model from the manufacturer’s website.

Updating to a newer BIOS can improve compatibility with CPU, drives and RAM that may solve potential conflicts at boot time. Updated firmware can also resolve bugs that cause boot issues. Just make sure power is not interrupted during the flash process or BIOS can be corrupted.

Updating the firmware on your hard drive or SSD to the version recommended for your system can also help stabilize drive boot behavior in some instances.

13. Replace the hard drive

If no other troubleshooting steps resolve the “boot device not found” error, the hard drive itself with your OS installed has likely completely failed. Hard drives fail all the time after years of use. The only option is to replace the boot drive in this case.

Install a new SATA HDD or even better an SSD for much improved system performance. Reinstall your operating system and restore your data from backup. As a preventative measure, be sure to regularly image or clone your boot drive so it can be easily replaced in the event of failure.

14. Troubleshoot drive connections and cables

Faulty cables, connectors, or loose connections could also be preventing your PC from detecting the primary boot drive and displaying the “boot device not found” message.

Carefully check all the connections involved in powering and communicating with your boot drive:

  • SATA data cable securely attached to drive and motherboard SATA port
  • Power cable properly connected from drive to power supply
  • Make sure the SATA and power ports on the drive itself are clean and free of damage
  • Try connecting the boot drive to a different SATA port on the motherboard in case the port is bad
  • Swap out SATA data and power cables for new ones in case cables are defective

Proper drive connections are required for your BIOS to detect it as a bootable device during the POST process.

15. Attempt data recovery

If reinstalling your OS or booting from other drives is unsuccessful, the original boot drive itself may be failing or already failed completely. In this worst case, attempt to recover any important data off the drive before replacement.

Connect the drive to another working computer as an external drive with a SATA to USB adapter or enclosure. See if the drive is detected in Windows File Explorer or Disk Management. If visible, quickly copy critical files to backup external storage.

If the drive is not recognized externally or crashes Windows Explorer when connected, use advanced data recovery software like Disk Drill to scan the drive and recover recoverable files. This may work where Windows cannot. Just avoid writing anything new to the failing drive during recovery efforts.

16. Clean install Windows fresh

After replacing the boot hard drive, reinstalling Windows fresh on a blank drive can eliminate any OS corruption that may have been preventing boot. This is a great time to clear out old junk and start over with a clean Windows install.

Ensure you have driver installation media for your various hardware like network adapters ready. Use another working computer to download the latest drivers. Perform a custom install of Windows 10 or 11 and install device drivers when prompted.

Once up and running, restore your data from backups taken prior to failure. Be cautious before reinstalling any sketchy applications that may have been involved in the original boot corruption.


That covers the wide range of steps you can take to troubleshoot and resolve the common but dreaded “boot device not found” error. With some effort, you can hopefully identify the underlying hardware issue preventing normal system boot and correct it to get your computer back online.

Always remember to keep reliable backups of your drive so important data is not lost if you do end up needing to replace the failed boot drive completely. Following proper backup practices can give you peace of mind next time boot issues strike.