How to Fix Missing Operating System Windows Error?

Summary: In the article, we delve into the common issue faced by Windows users known as the “Missing Operating System” error. We explore the causes behind this error, which occurs when the computer fails to locate essential files for booting up the operating system. Our objective is to provide readers with insights on effectively addressing this problem. Furthermore, we address the potential data loss that can accompany this error, offering guidance on how to handle such situations. Stay informed and prepared with our comprehensive guide to the missing operating system error in Windows.

Content Table:

What is Missing Operating System means?

A missing operating system is an error that occurs when you try to boot a Windows operating system. This indicates that the computer can’t find the required files to boot the operating system. A missing operating system occurs due to several reasons.

Causes for Missing Operating System Error

  • System files Corruption: If the files responsible for booting Windows become corrupted, it can prevent the operating system from loading.
  • Damage to the hard drive: If the hard drive containing the operating system files gets corrupted, the computer is not able to locate the files to boot.
  • Incorrect boot order: If the BIOS settings are configured to boot from an incorrect device, the operating system cannot load.
  • Corruption in Master Boot Record (MBR): The MBR is a major part of the boot process that helps the computer find the operating system. If the MBR is corrupted, then the computer cannot locate the files.
  • Virus/malware infections: A virus or malware infection can cause damage to the operating system files, which then prevents booting the operating system.
  • Accidental system file deletion: Deleting or moving system files can cause considerable damage to the operating system, resulting in the “Missing Operating System” error.

How to Repair Missing Operating System Windows?

Facing missing operating system error on your Windows system is a sad affair when you depend on your computer for work and other important tasks. There are solutions you can try to repair the issue. We will provide some of the simple once you can use to repair the missing operating system error message on a Windows computer.

Method 1: Check boot order in BIOS

Boot order is the order in which computer firmware attempts to boot from different devices. The boot order determines the sequence in which the computer check each device for operating system files. Usually, it set to check the hard drive first, where the operating system normally installed. But it is important to check the boot order to conform that the computer boot from the correct device to avoid missing operating system error message.

  • Restart your computer and press the designated key during startup to enter the BIOS

Note: The key to enter BIOS setup may vary depending on manufacturer.

  • When you enter the setup, look for the Boot or Boot Order
  • Check the boot order to ensure that the hard drive your operating system installed is first in the boot sequence.
  • If not, use the arrow keys to select the correct drive and move it to the top of the list.
  • Save the changes and exit the setup.

Note: The steps to check the boot order may vary depending on your computer’s manufacturer and BIOS/UEFI version.

Method 2: Check if BIOS detect the hard drive

If the boot order is not the issue, then you should check is the hard drive is detected by the BIOS. Follow steps below,

  • Restart your computer and enter the BIOS
  • In the menu find IDE Primary Master, IDE Primary Slave, and IDE Secondary Master.
  • Check they detect or not, if no disk or None or Not Detected is shown then the BOIS do not detect the drive.

If the BIOS is not detecting the hard drive, it means an issue with hardware or BIOS settings. Check the hard drive connection to the computer. If the cable shows any damage, then you should change it and that should fix it.

Method 3: Diagnose the hard drive

When the problem stays even after fixing the connection then it could be an issue in the hard drive itself. So, you should diagnose the drive to find and fix the hard drive issues. BIOS utilities come a built-in diagnostics tool to help diagnose the hard drive or other storage devices.

  • Restart the system and enter the BIOS
  • Look for the Diagnostics or Tools section in the menu.
  • Select Hard Drive Self Test and hit Enter to start the scan.

You will get one of the two results,

All tests were successful: The hard drive is not the issue. You can continue to next method.

The test was unsuccessful: It is a hard drive issue. You should replacement it.

Method 4: Reset BIOS to default

Now that we ruled out hard drive issues, resetting the BIOS to default settings is a useful troubleshooting step. This will restore the BIOS to original settings, which resolve any configuration issues that may be causing problem.

  • Restart the system and enter the BIOS
  • In the BIOS menu active default setup options, which include Load Optimal Defaults, Load Optimized Defaults, Get Default Values, Load Setup Defaults, etc.
  • Now press F10 to save changes and exit the menu.

Note: Resetting the BIOS will erase custom settings. You may need to reconfigure the settings.

Method 5: Rebuild master boot record (MBR)

If you try and fail with above methods, then it could be damage to your master boot record (MBR) files. The MBR contains essential information about the disk partition layout and how the disk boots. If damaged, this could cause various issues, including missing operating systems. Rebuilding the MBR may help to resolve the issue. Here are the steps to rebuild the MBR using Windows installation media,

  • Insert the Windows installation media (CD/DVD or USB drive) and restart the computer.
  • Enter the Boot menu and select Boot from Windows installation media.
  • In the Windows Setup screen, select your language preferences, then click on Next.
  • Now click on Repair your computer in the bottom left corner.
  • Then click on Troubleshoot and select Advanced options.
  • Select Command Prompt from the list of advanced options.
  • In the Command Prompt window, type the following and press Enter after each command.
    • bootrec/FixMbr
    • bootrec/FixBoot
    • bootrec/ScanOS
    • bootrec/RebuildBcd

When the process completed, remove the Windows installation media, and restart your computer.

Method 6: Active correct Windows partition

The other scenario for the missing operating system is when the partition containing the Windows operating system is not active. This is important when you use Legacy BIOS + MBR mode. We can active the partition using Diskpart utility.

  • Insert the Windows installation media (CD/DVD or USB drive) and restart the computer.
  • In the Windows Setup go to Repair your computer
  • Now click on Troubleshoot and select Advanced options and Command Prompt.
  • Type diskpart and press Enter.
  • Type list disk and press Enter to display a list of all the partitions on your computer.

Note: Find and note down the number of the disk that contains the Windows operating system. It is usually the disk with the largest capacity.

  • Type select disk X (replace X with the above-mentioned number) and press Enter.
  • Type list volume and press Enter to display a list of all the partitions on your computer.

Note: Find and note down the number of the partition that contains the Windows operating system. It is usually the partition with the label System.

  • Type “select volume X” (replace X with the number of the Windows partition) and press Enter.
  • Type “active” and press Enter to activate the Windows partition.
  • Type “exit” to close the Command Prompt window.

Method 7: Install a new Windows

Now that we have exhausted all the method to fix the missing operating system, the only way to access your computer is to install a new Windows operating system. You can use the Windows installation media and install new Windows to your system by following the on-screen instructions.

Can You Recover Data from Missing Operating System Error?

When a missing operating system error occurs, there is a chance of loss of data. The data may lose while repairing the error or when installing a new Windows operating system. But, with a right software, you recover lost files and data. One such software is SFWare Data Recovery software, it designed to recover lost, deleted, or formatted data from a wide range of storage devices.

Steps to recover data using SFWare Data Recovery Software

Before starting the recovery process, download and Install SFWare Data Recovery software on your system.

Free Download for WindowsFree Download for Mac

  • Launch the tool; on the main screen, click on Recover Drives/Partition.

SFWare Data Recovery Software Home Screen

  • Click on Drive/Partition Recovery on the next screen, which will show you storage devices.

SFWare Data Recovery Software Select Drive/Partition Recovery

  • Select the device from which you want to recover and click Next. This will initiate a scan process.

SFWare Data Recovery Software Select Device to Recover

Note: When the scan to complete, you can see all the partitions available.

  • Select the partition you want to recover and click Next; this starts scanning the partition for recoverable data.

SFWare Data Recovery Software Select the Partition to Recover

Note: When the scan is completed, it displays the data in a window with a Data view and File type view.

SFWare Data Recovery Software Select File Types to Recover

  • You can double-click on the data to preview the data. Saving the data to your desired location if you are satisfied.

SFWare Data Recovery Software Preview File Screen

Note: Don’t choose the exact location to save, which will corrupt the data.

Precaution to avoid data loss from your system

  • Do not turn off or restart your computer during the installation or update.
  • Avoid interrupting the boot process.
  • Ensure that your computer is not infected with malware or viruses.
  • Regularly scan your hard drive for errors and bad sectors.
  • Keep your computer’s BIOS up to date and configure the boot order correctly.
  • Avoid physically damaging your computer’s hard drive or storage devices.


When faced with a missing operating system error, it looks like a tough situation. But with the simple steps given above, you can easily fix the error and start using your system in no time. Even if you are having a data loss scenario, we even provide a solution. So, if you are facing a situation to fix a missing operating system, try out the solutions and let us know how it helped you.

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