Fixed: The Critical Error ‘Operating System Not Found’ on Acer

User Case: How to Find Operating System on Acer Laptop

“Hi, I have a problem with my laptop. When I turn him on, it starts showing "Operating System Not Found". I am mind in very bothered by this. Does anyone have the same problem or know the solution, please?”

-Question from Acre Community

If you encounter a "No operating system found error" when booting your Acer computer, it may be due to the following reasons.

• The basic input/output system (BIOS) does not detect the hard disk.
• The hard drive is corrupted.
• The physical hard drive has an incorrect or malformed master boot record (MBR) in sector 0.
• An incompatible partition is marked as active.
• A partition that contains an MBR is no longer active.

How to Fix Operating System Not Found on Acer

Here are 4 tested methods, from the simplest to the most complex. To solve this problem, use one of the following methods, depending on your situation.

💛 Note: Microsoft recommends that if you are still having problems after basic troubleshooting, contact your hard drive manufacturer. Manufacturers often have specific utilities for their hard drives that will better troubleshoot damaged or corrupted areas. The manufacturer can also confirm the proper BIOS settings.

👉 Solution 1. Confirm that BIOS Can Detect the Hard Drive 👉 Solution 2. Resetting the BIOS on an Acer laptop 👉 Solution 3. Fix the Boot Records via Media Creation Tool 👉 Solution 4. Restore Computer with Bootable Media

Solution 1. Confirm that BIOS Can Detect the Hard Drive

If you encounter an "Operating System Not Found" error when booting your computer, you first need to make sure there is no problem between the hard drive and the BIOS.

1. When you press the power button to turn on your computer, press and hold F10, F2, F12, F1, or DEL to enter the BIOS. This key will vary from machine to machine. Below is a list of the most commonly used BIOS hotkeys by brand.

• Acer: F2 or DEL
• ASUS: F2 for all PCs, F2 or DEL for motherboards
• Dell: F2 or F12
• HP: ESC or F10
• Lenovo: F2 or Fn + F2
• Lenovo (Desktops): F1
• Lenovo (ThinkPads): Enter + F1
• MSI: DEL for motherboards and PCs
• Microsoft Surface Tablets: Press and hold volume up button.
• Origin PC: F2
• Samsung: F2
• Sony: F1, F2, or F3
• Toshiba: F2

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

3. If everything looks good in your BIOS menu, skip to the third solution. If you don't see a hard drive listed, look at the second solution.

Solution 2. Resetting the BIOS on an Acer laptop

If your machine does not recognize your hard drive, it may also cause an "Operating System Not Found" error. For the non-technical user, the only simple solution is to try resetting the entire BIOS menu to its default values.

At the bottom of the BIOS menu, you should see a key to Setup Defaults or reset the BIOS. On some machines it is F9, but it may be different on your machine. Confirm your decision when prompted, then reboot the machine.

Solution 3. Fix the Boot Records via Media Creation Tool

Microsoft Windows relies on three main types of records to boot your machine. They are the Master Boot Record (MBR), the DOS Boot Record (DBR), and the Boot Configuration Database (BCD). If any of these three records are damaged or corrupted, you will most likely encounter a "Operating System Not Found" message on Acer laptop. Thankfully, you can fix this problem by following the instructions below.

1. Prepare a USB flash drive and create a removable Windows installation drive on another computer that is running well. Use Microsoft's Media Creation Tool to create some Windows 10 installation media.
2. Once the tool is ready, you need to use it to boot your Acer machine that is having errors. Then press a specific key to enter the BIOS menu and change the boot order in the BIOS menu.
3. Then 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.

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

• bootrec.exe /fixmbr
• bootrec.exe /fixboot
• bootrec.exe /scanos
• bootrec.exe /rebuildbcd

5. Each command may take a few minutes to complete. Once all the processes are complete, restart your computer and see if the "Operating System Not Found" error still appears on Acer machine.

Solution 4. Restore Computer with Bootable Media

If you are suffering from the "Operating System not found" error on Acer, you can also use bootable media to help you get your problematic PC back to normal. You can create bootable media on another working Acer computer and then reset your problematic device with the help of third-party reliable software. 

AOMEI Backupper Professional, the most useful backup and restore software, can easily help you create bootable media and system backup. Then, you can plug this media tool into your computer with "OS not found" error and perform Windows 10 factory reset from boot.

Below, I will show you how to use this software to create bootable media on another Windows 10 computer in good working condition. After creating it, you need to create a system backup, which will help you to perform a "Universal Restore" on the Windows 10 PC that is having problems.

1. Download AOMEI Backupper on your working computer and install it. 

2. Once the installation is complete, launch the freeware. Click Tools -> Create Bootable Media in order.

3. Then choose the type of emergency bootable disc that you're trying to create. Here we select Windows PE – Create bootable disc based on Windows PE and click Next to continue.

Tip 📌: Linux-based bootable media allows you to use only the basic features of AOMEI Backupper, while Windows PE allows you to access the full functionality.

4. Then select the USB Boot Device to create a Windows 10 bootable media, and click Next to run the process.

5. After creating the bootable media, you can create a system backup to this USB.
6. Once the whole operation is complete, insert this bootable media into your Acer device that is having "laptop operating system not found" issue on Acer. After booting, it will automatically enter the AOMEI recovery environment, and then you can perform a System Restore.

Final Words

If you have encountered the problem that "Operating System Not Found" in Acer laptop or desktop, you can refer to this article for four ways to restore your computer to normal. To prevent you from experiencing these system problems in the future, it is recommended that you back up your system in advance. In this way, if you encounter similar problems in the future, such as "Startup Repair Is Checking Your System for Problems", you can do a system restore with the help of AOMEI Backupper Standard to quickly fix your computer problems.