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

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

Out of all the errors, glitches, and problems you might come across while using Windows 10, a handful of notifications can make you truly scared, such as the “Operating system not found” screen.

The prospect of losing your entire media collection, important school essays or ongoing projects at work makes you feel like you’re “crazy”. Keep calm! Your data is still there. You can fix this and get everything back.

Let’s see how to fix the “Operating system not found” error on Windows 10 through the following article!

1. Check the BIOS

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

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

The BIOS menu itself differs between devices. More broadly, you 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 in your BIOS menu looks good, skip to step three. If you don’t see the hard drive listed, go to step two.

2. Reset BIOS

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

How to do details in the article: 3 simple ways to reset BIOS settings.

If the operating system still cannot be found, you can stop reading this article. Unless you know a lot about building a computer, you will need to take it to a computer repair shop.

3. Edit Boot Records

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

If any of these three records are corrupt or corrupt, there’s a high chance you’ll get the message “Operating system not found”.

Thankfully, fixing these records isn’t as complicated as you might think. You only need a portable Windows installation drive. Use Microsoft’s Media Creation Tool to create installation media for Windows 10.

When the tool is ready, you need to use it to boot your computer. Depending on the device, you may only need to press a single key during the boot process or you may need 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, and click Next. On the next screen, select Repair your computer .

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

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

Each command can take a few minutes to complete. After all the processes are finished, reboot the PC and see if it boots successfully or not.

4. Enable or disable UEFI Secure Boot

Enable or disable UEFI Secure Boot

Almost every Windows machine is shipped with UEFI firmware and Secure Boot. However, in some cases it may not work. For example, if Windows is installed on 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.

Therefore, be cautious when enabling or disabling UEFI Secure Boot and see if it makes a difference. You will make adjustments in the BIOS menu. Usually the option is called Secure Boot and can be found under the Security tab .

5. Activate the Windows partition

Activate the Windows partition

It is possible that the Windows installation partition has been disabled. You can fix it using Windows’ native diskpart tool. To do the following, you will need a Windows USB installation.

Turn on the machine 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 mounted drives. Note down the number of drives you need. Usually, it’s the biggest.

  • Use DiskPart to format and clean portable hard drive in Windows 10

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

Now, type list volume and press Enter. It will show you all the partitions on the drive you have selected. Set up the installed Windows partition and write down the number, then enter select volume [number] , again replacing [number] with the number you just wrote down.

Finally, type active and press Enter. To see if the process is successful, reboot the machine.

6. Use Easy Recovery Essentials

Using Easy Recovery Essentials

Easy Recovery Essentials is a third-party application for troubleshooting 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.

Just download the app, burn the ISO to a CD and use the CD to boot. An application wizard will help you through the repair process.

Refer to some more articles below:

  • 4 Ways to Fix Unformatted USB: “Windows was unable to complete the format”
  • Summary of some ways to fix Windows 10 crashes, BSOD errors and restart errors
  • Fix abnormally high CPU error caused by TiWorker.exe on Windows 10 / 8.1 / 8

Good luck!