Non System Disk or Disk Error
Non System Disk or Disk Error

The “Non-System Disk or Disk Error” message is a common boot error in Windows computers that typically appears when the BIOS cannot find a bootable operating system on any of the storage devices included in its boot path. This error can be caused by several factors, such as incorrect BIOS settings, loose or damaged hard drive connections, or a corrupted Master Boot Record (MBR). Here’s a comprehensive guide to troubleshoot and resolve this error:

Fix 1: Remove Non-Bootable Storage Devices

  1. Shut Down Your System: Press and hold the power button for 10 seconds to completely shut down your computer.
  2. Detach from Power Source: Unplug your computer from the power source.
  3. Remove External Devices: Carefully remove any external USB devices, including external hard drives.
  4. Check for Discs in Drive: Ensure there are no CDs or DVDs in the disk tray.
  5. Reconnect and Restart: Reconnect the power cable and turn on the system. The BIOS should now boot from the system drive​​.

Fix 2: Re-Arrange Boot Sequence in BIOS/UEFI

  1. Access BIOS/UEFI: Restart your computer and press the key (usually Delete, F2, F8, or F10) to enter BIOS/UEFI settings.
  2. Adjust Boot Order: In the BIOS/UEFI settings, navigate to the “Boot” tab and rearrange the boot sequence to prioritize the HDD/SSD containing the Windows folder.
  3. Save and Exit: After adjusting the boot order, save the changes and exit the BIOS/UEFI. The computer will restart with the new settings​​.

Fix 3: Check and Reinstall Hard Drive

  1. Power Down and Disconnect: Turn off your computer and disconnect it from the power source. If using a laptop, remove the battery.
  2. Open Casing: Open the computer’s casing (or the back cover for laptops).
  3. Inspect HDD/SSD Connection: Check the SATA/IDE cable connection to the motherboard. Ensure it’s secure and not loose or damaged.
  4. Reinstall the System Disk: After inspection, reinstall the system disk and close the casing or screw up the back cover​​.

Fix 4: Rebuild Master Boot Record (MBR)

  1. Force Shutdown and Boot into Repair Mode: Turn off your system, then turn it back on. Force shutdown by holding the power button during startup. Repeat this 1-2 times until the system enters ‘Automatic Repair‘ mode.
  2. Access Advanced Options: On the ‘Automatic Repair’ screen, click “Advanced options”.
  3. Use Command Prompt: Navigate to “Troubleshoot” > “Advanced options” > “Command Prompt”.
  4. Rebuild MBR: In the Command Prompt, execute the following commands to rebuild the MBR: bootrec /fixmbr, bootrec /fixboot, and bootrec /rebuildbcd​.

Additional Steps

  • Remove All Non-Bootable Media: Remove any media that the computer cannot boot from, including DVDs, CDs, USB flash drives, and floppy disks​​.
  • Run Disk Check: If you suspect the hard drive is damaged or corrupted, run a disk check in Windows. Open Disk Management, right-click on the boot device, select ‘Properties’, then ‘Tools’, and finally ‘Check’​​​​.
  • Check BIOS Settings: Ensure the correct boot device is selected in the BIOS settings. Refer to your computer’s manual for instructions​​.


Resolving the “Non-System Disk or Disk Error” involves a series of steps to ensure the BIOS can successfully locate and boot from the correct drive. These steps include removing non-bootable media, checking and securing hard drive connections, adjusting BIOS settings, and rebuilding the MBR if necessary. If these steps do not resolve the issue, it may indicate a more severe hardware problem, and you may need to consult a professional technician.

Eric Chan

Hi! I’m Eric and I work on the knowledge base at  You can see some of my writings about technology, cellphone repair, and computer repair here.

When I’m not writing about tech I’m playing with my dog or hanging out with my girlfriend.

Shoot me a message at if you want to see a topic discussed or have a correction on something I’ve written.

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