Fixing the Operating System Not Found Error: A Simple Guide
Learn how to resolve the “Operating System Not Found” error on your PC with this detailed guide. Understand its common causes, including disconnected drives, boot misconfigurations, or corrupted MBR, and explore 12 practical solutions to fix the issue. Back up your data before making changes, and troubleshoot effectively by using tools like BIOS settings, command-line utilities, or bootable USBs.
For additional help, use our free chatbot, specially programmed to assist with technical troubleshooting.
Key Takeaways
- If your PC displays the “Operating System Not Found” error, common causes include a disconnected drive, incorrect boot configuration, or a corrupted Master Boot Record (MBR).
- You can resolve the error by checking BIOS settings, repairing the system via command-line tools, or resetting the boot order.
- Always back up your data before initiating critical repairs or configurations to avoid data loss during the troubleshooting.
Step-by-Step Guide to Fixing the “Operating System Not Found” Error
This guide will walk you through 12 proven techniques to troubleshoot and resolve the “Operating System Not Found” error on your computer effortlessly.
1. Disconnect Peripherals and Restart Your PC
Unnecessary connected devices, such as USB drives or external hard disks, can disrupt the boot process.
Steps:
- Remove all plugged-in USB drives, external hard drives, and peripherals.
- Restart your computer.
If the issue persists, proceed to the next step.
Expert Tip: If you rely on portable operating systems or bootable disks, tools like EaseUS OS2Go can help you build a bootable USB for emergencies.
2. Check if the Hard Drive Is Recognized in BIOS
If your hard drive is missing in BIOS settings, the system won’t detect the operating system.
Steps:
- Restart your computer and press the appropriate key (e.g.,
F2,Del,Esc) to access the BIOS setup. - Go to the Storage Information or Boot Options section.
- Confirm that your primary hard drive is listed.
- If not, reseat the hard drive cable or replace it with a functioning one.
Affiliate Tool: If you suspect data damage, use MiniTool Power Data Recovery to recover lost data before replacing the drive.
3. Test the Hard Drive for Damage
Faulty hard drives can display boot errors.
Steps:
- Enter BIOS and locate the Diagnostics or Hardware Test option.
- Run the self-test to confirm the status of the drive.
If the test fails, consider using MiniTool Partition Wizard for partition repair or EaseUS Backup Center to back up remaining data.
4. Run Automatic Startup Repair
Windows’ built-in repair tools can automatically resolve boot errors.
Steps:
- Insert your Windows installation disk or USB and boot from it.
- Click Repair your computer > Troubleshoot > Advanced Options > Startup Repair.
- Allow your system to attempt the repair.
Pro Tip: Startup problems often stem from incompatible settings. Use EaseUS Todo PCTrans to migrate essential settings and files before rebuilding.
5. Disable (or Enable) Secure Boot in BIOS
UEFI Secure Boot settings can sometimes interfere with the booting sequence.
Steps:
- Access BIOS during startup (
F10,F12, etc.). - Locate the Secure Boot option under the Security tab.
- Switch the toggle to the opposite state (e.g., enable or disable).
- Save and exit BIOS, then restart the PC.
Expert Insight: UEFI-based systems often work better with newer boot managers. Consider switching to modern partitioning tools like MiniTool ShadowMaker for better compatibility.
6. Reset BIOS to Default Settings
Incorrect BIOS configurations can also cause boot issues.
Steps:
- Open the BIOS settings.
- Look for “Reset to Defaults” or “Load Optimal Settings” options.
- Save the changes and exit.
Why it helps: Hardware misconfigurations or previous changes may be resolved by restoring defaults.
7. Activate the Windows Partition Using Command Prompt
Inactive system partitions can prevent Windows from booting.
Steps:
- Boot into Command Prompt using a bootable USB or DVD.
- Enter the following commands:
diskpart list disk select disk 0 list partition select partition 1 active exit - Reboot your computer.
Related Tools:
- Recover deleted partitions with EaseUS Partition Master.
8. Rebuild the Master Boot Record (MBR)
During Windows startup, a corrupted MBR can trigger the error.
Steps:
- Use the Windows recovery disk to access the Command Prompt.
- Input the following commands:
bootrec /fixmbr bootrec /fixboot bootrec /rebuildbcd - Restart the PC after exiting the Command Prompt.
Affiliate Recommend: EaseUS Backup Center can help save your system before rebuilding the MBR.
9. Check Boot Priority Order
Incorrect boot order might lead to this error.
Steps:
- Access BIOS and navigate to the boot priority sequence.
- Set the drive with the operating system as the first boot device.
- Save settings and restart.
10. Check for Disk Errors
Running a disk check can identify and correct filesystem issues.
Steps:
- Open Command Prompt via the recovery environment.
- Run the following command:
chkdsk /f /r C: - Let the process complete and reboot.
Expert Note: Use EaseUS DupFiles Cleaner to remove unnecessary junk files and improve performance post-repair.
11. Switch Between UEFI and Legacy Boot Modes
Boot mode incompatibility often causes startup problems.
Steps:
- Enter the BIOS and look for Boot Mode settings (UEFI or Legacy).
- Switch to the alternate mode.
- Restart your computer.
12. Reinstall or Recover Windows Using Bootable USB
If all else fails, reinstalling your OS might be the most effective solution.
Steps:
- Use Wondershare Recoverit to back up important files before reinstalling Windows.
- Create a bootable installation media.
- Reinstall the OS following the on-screen instructions.
Frequently Asked Questions (FAQs)
1. Why does my computer say “Operating System Not Found”?
This occurs when your computer cannot detect a working operating system. Common causes include a misconfigured BIOS, disconnected hard drive, or corrupted boot files.
2. Can I recover data after the “Operating System Not Found” error?
Yes, tools like MiniTool Power Data Recovery or EaseUS Data Recovery can help retrieve your files.
3. How do I prevent this error in the future?
- Regularly back up your system using tools like MiniTool ShadowMaker.
- Avoid making abrupt shutdowns.
- Address minor disk errors early with
chkdsk.
Final Advice: Troubleshooting boot problems can be challenging, but following this structured guide will ensure a higher chance of resolving the issue systematically. Always handle repair tools with care!
