How to fix Operating system not found error on Windows

Of all the errors, glitches, and problems you can encounter while using Windows 10, a few messages can be truly terrifying, such as the “Operating system not found” screen.

The prospect of losing your entire media collection, your important school papers, or your ongoing projects at work can make you feel like you’re going crazy. Stay calm! Your data is still there. You can fix this and get it all back.

Let's see how to fix the error "Operating system not found" on Windows 10 through the following article!.

Table of Contents

• Causes of the error "Operating system not found"
• How to fix "Operating system not found" error on Windows
  • 1. Check BIOS
  • 2. Reset BIOS
  • 3. Repair Boot Records
  • 4. Enable or disable UEFI Secure Boot
  • 5. Activate Windows partition
  • 6. Use Easy Recovery Essentials

Causes of the error "Operating system not found"

There are a few simple reasons why this error might occur, and it is unlikely that your important data has been deleted. Here are some of the causes of this error:

• BIOS is configured incorrectly
• Boot Record is corrupted
• Hard drive is damaged or inaccessible

Note : This error can occur on any computer running Windows 11, Windows 10, Windows 8, Windows 7, Windows Vista or Windows XP.

How to fix "Operating system not found" error on Windows

Some basic troubleshooting measures

Before you apply any in-depth fixes for the "Operating system not found" error, you can try some of the following simple solutions. Sometimes the error simply appears due to a temporary glitch, so these methods will quickly help you eliminate the problem without taking much time and effort.

• Restart your computer. The error may be a temporary glitch that a restart will fix.
• Disconnect any unnecessary flash drives, remove the disc if you have one in the drive, and remove any floppy disks. Your computer may be trying to find a suitable operating system on one of those devices, and if it can’t, it may display an “Operating system not found” error.
• Reconnect the hard drive's power and data cables. A loose or unplugged cable may be the cause of the error.

1. Check BIOS

You need to check two things in the BIOS . First, you need to make sure that your computer recognizes your hard drive. Second, you need to make sure that the drive you installed Windows on is listed as the preferred boot drive.

The method for entering BIOS varies by manufacturer. Typically, you will need to press Escape, Delete , or one of the Fn keys . You will see a message on the screen telling you which key is correct during the boot process.

The BIOS menu itself also varies from device to device. Generally speaking, you’ll need to locate the Boot tab along the top of the screen. (You can only use your keyboard to navigate the BIOS menu.)

In the Boot tab, go to the Hard Drive option and press Enter. Make sure Hard Drive is listed above USB Storage, CD\DVD\BD-ROM, Removable Devices , and Network Boot . You can adjust the order using the + and - keys .

If everything looks fine in your BIOS menu, move on to step three. If you don't see your hard drive listed, move on to step two.

2. Reset BIOS

If your computer is not recognizing your hard drive, there are many possible causes. For non-tech-savvy users, the only easy solution is to try resetting the entire BIOS menu to its default values.

Detailed instructions are in the article: 3 simple ways to reset BIOS settings .

If the operating system is still not found, you can stop reading this article. Unless you know a lot about building computers , you will need to take your computer to a computer repair shop.

3. Repair Boot Records

Windows relies primarily on three records to boot your computer. They are the Master Boot Record (MBR) , DOS Boot Record (DBR), and Boot Configuration Database (BCD).

If any of these three records are corrupted or faulty, there is a high chance that you will encounter the "Operating system not found" message.

Luckily, fixing these records isn't as complicated as you might think. All you need is a portable Windows installation drive. Use Microsoft's Media Creation Tool to create Windows 10 installation media.

Once the tool is ready, you need to use it to boot your computer. Depending on your device, you may only need to press a single key during the boot process, or you may have to change the boot order in the BIOS menu.

Finally, you will see the Windows Setup screen. Enter your preferred language, keyboard, and time format, then click Next. On the next screen, select Repair your computer .

Next, navigate to Troubleshoot > Advanced Options > Command Prompt . When Command Prompt loads, enter the following three commands. Press Enter after each command:

bootrec.exe /fixmbr
bootrec.exe /fixboot
bootrec.exe /rebuildbcd

Each command may take a few minutes to complete. Once all the processes are finished, restart your PC and see if it boots successfully.

4. Enable or disable UEFI Secure Boot

Most Windows machines ship with UEFI firmware and Secure Boot enabled. However, in some cases, it may not work. For example, if Windows is installed on a GUID Partition Table, it can only boot in UEFI mode. Conversely, if Windows 10 is running on an MBR drive, it cannot boot in UEFI mode.

So, it's worth being cautious about enabling or disabling UEFI Secure Boot and seeing if it makes a difference. You'll make the adjustments in the BIOS menu. Typically, the option is called Secure Boot and can be found in the Security tab.

5. Activate Windows partition

It is possible that the Windows installation partition has become disabled. You can fix it using Windows' native diskpart tool. To perform the following steps, you will need a Windows installation USB.

Turn on your computer and boot from the tool. As in step three, you will need to enter your language preferences, etc., then click Next , select Repair your computer and go to Troubleshoot > Advanced Options > Command Prompt .

In Command Prompt , type diskpart and press Enter , then type list disk and press Enter. You will see a list of all the drives attached to your machine. Note the number of the drive you need. Usually, it is the largest one.

• Use DiskPart to format and clean up portable hard drives on Windows 10

Next, type select disk [number] , replacing [number] with the number mentioned above. Press Enter.

Now, type list volume and press Enter. It will show you all the partitions on the drive you selected. Select the partition where Windows is installed and note down the number, then type select volume [number] , again replacing [number] with the number you just wrote down.

Finally, type active and press Enter. To see if the process was successful, restart your computer.

6. Use Easy Recovery Essentials

Easy Recovery Essentials is a third-party application that specializes in fixing boot problems. If none of the previous 5 steps worked, then you should try this tool.

In addition to fixing the "Operating system not found" error, Easy Recovery Essentials can also resolve other common boot error messages, including INACCESSIBLE_BOOT_DEVICE, INACCESSIBLE_BOOT_VOLUME , UNMOUNTABLE_BOOT_VOLUME , BOOTMGR is missing , The Boot Configuration Data for your PC is missing or contains errors, An error occurred while attempting to read the boot configuration data, boot.ini not found, etc.

Simply download the app, burn the ISO to a CD , and boot from the CD. The app's wizard will guide you through the repair process.

Good luck!

See more articles below:

• 4 ways to fix USB error that cannot be formatted: “Windows was unable to complete the format”
• Summary of some ways to fix Windows 10 freezing errors, BSOD errors and reboot errors
• Fix unusually high CPU usage due to TiWorker.exe on Windows 10/8.1/8