How to Fix the ‘Operating System Not Found’ Error


Your computer might not be able to find the operating systems it needs to boot into. This error will appear as a simple message on a black screen: “Operating System Not Found“. Although this might seem alarming, it’s not likely that your files have disappeared.

The ‘Operating System not Found’ Error

This could be for a few simple reasons, but it is unlikely that your sensitive data was erased. These are the possible causes of this error.

  • BIOS was misconfigured
  • Boot records are destroyed
  • Hard drive damaged or unavailable

This error can be found on any computer that runs Windows 11, Windows 10, Windows 8 or Windows 7, Windows Vista, Windows XP, or Windows 11.

How to fix the “Operating system not found” error

  1. Restart your computer. It could be temporary and a restart will resolve it.

  2. Disconnect any flash drives that are not needed, eject the disc from the drive if it’s there, and then remove all floppy disks. The computer may be trying to find the right OS for one of these devices. If it fails, it may display an ” Operating System Not Found” error.

  3. Open BIOS, and ensure that the boot device the operating system is installed is listed in the list. Change the boot order to make it so.

    This is crucial because your computer will think there is an OS on the flash drive or disc that has priority, but it doesn’t, and will throw an “not found” error.

  4. Depending on the current setting, toggle UEFI Secure Boot off or on. Windows will be able to boot in UEFI mode depending on whether it is on a GUID Partition Table or an MBR disc. You can disable or enable Secure Boot to determine if the error is related.

    This is done through the BIOS setup utility (see Step 3 for instructions) or through the Safetytab. You can toggle Secure Boot from whatever it is to what it is currently, so either Enabled or Disabled.

    After this step, restart your computer. If the error persists, you can revert the setting to the original and then proceed with the next step.

  5. Reset the BIOS to its factory default settings. You might need to reset every BIOS customization in order to remove any files that were hiding or corrupting the operation system.

    You can fix the ” Operating System failed to find” error by using a BIOS reset. This is done by looking for a reset option in the BIOS setup utility. You might need to press a function key such as F9 or a menu option called RESET BIOS. The BIOS manufacturer will determine the steps that you should take.

  6. Restore the boot records. For normal boot processes, it is vital to have valid boot records. You might get the error ” Operating System Not Found” if the master boot record (MBR), or the boot configuration data store (BCD) are missing or corrupted.

    You will need to insert a flash drive or an installation disc to access Windows. You can learn how to do this in Windows11/10/8 here. Windows 7 users ( hier) will need similar steps. Vista users (hier_) can also follow the same steps.

    Start by Rebuilding the BCD using this command (open the link to see all the steps required to reach the Command Prompt, where you can type this).

    bootrec.exe /rebuildbcd

    You can still be in Command Prompt. After the previous command has finished, you can enter this one.

    bootrec.exe /fixmbr

    Reboot your computer to verify that the error ” Operating System Not Found” has been corrected.

    If you are using Windows XP , this article will show you how to fix the MBR. You can also repair some Windows XP boot files by repairing your boot.ini.

  7. To activate the Windows partition, use the diskpart command. It could have been disabled for some reason. This would explain why you are seeing the ” Operating System Not Found” error.

    Follow the above steps to access Command Prompt on the installation CD. Then, enter the following command:


    Followed closely by:

    list disk

    This command will allow you to select the disk that corresponds with the installation of the operating system. Most people will only see one from the list.

    select disk 0

    This will list all partitions on the disk.

    list volume

    This command will allow you to select the partition on which Windows is installed.

    select volume 2

    This command will activate the volume.


    Windows should restart normally after you have fixed the error ” Operating System Not Found“. To restart the operating system, exit Command Prompt.

  8. Reconnect the power supply and data cables to your hard drive. The error could be caused by unplugged or loose cables.

  9. Install the Windows operating system. It is possible that the error “Operating System Not Found” could be literal. It is possible that malware has deleted the OS from your hard drive.

    Step 10 is the last resort if you are unable to access your hard drive in order to reinstall the operating systems.

  10. A faulty hard drive may be the reason you are still experiencing the error. To fix the error, replace the hard drive with a new version of the operating software.