Windows Boot Manager Missing from BIOS Fix Using PC

Imagine starting your computer only to be greeted by an unsettling message - "Windows Boot Manager Missing." This issue can be frustrating and worrisome, especially if you rely on your computer for work, entertainment, or personal use. In this article, we will delve into the reasons why the Windows Boot Manager can go missing from the BIOS in Windows 10 and how you can resolve this issue to bring your system back.

What is Windows Boot Manager on your PC?

Windows Boot Manager is a critical component that plays a pivotal role in the startup process of your operating system. When you turn on your computer, the BIOS or UEFI firmware looks for the Windows Boot Manager, which then loads the Windows kernel and initiates the boot process. If the Boot Manager is missing or corrupted, your computer won't be able to start the operating system properly.

The Windows Boot Manager file is normally found on the System Reserved disk; however, if you do not have a System Reserved partition, the file must be found on your system partition, which is typically the C drive. You should also be aware that the BOOTMGR file is read-only and cannot be edited.

Why Windows Boot Manager missing from BIOS on Windows 10/11?

Why will the "Windows Boot Manager missing" error happen? Boot Manager files can read Boot Configuration Data, and execute winload.exe to start your system. Any mistake in any aspect may lead to the occurrence of this problem.

▶ Corrupted Boot Configuration Data (BCD)
The BCD is a crucial database that stores boot-related settings. If it gets corrupted due to system errors, power outages, or malware, the Boot Manager won't be able to locate the operating system, leading to its absence during boot-up.

▶ Incorrect boot order or boot device priority
Sometimes, the Boot Manager might not be missing, but the system could be attempting to boot from the wrong device, like an external USB drive or an empty CD/DVD drive. This can give the impression that the Boot Manager is missing.

▶ Faulty or unplugged hard drive cable
A loose or damaged hard drive cable can result in the system failing to detect the boot drive. As a consequence, the Boot Manager can't find the necessary files to initiate the operating system.

▶ Corrupted Master Boot Record (MBR)
The Master Boot Record is a small section on the boot drive that contains essential information about the disk's partitions and how to boot the operating system. Corruption of the MBR can prevent the Boot Manager from loading.

▶ Malware or virus attacks
Malicious software can tamper with critical system files, including those related to the Boot Manager. If malware corrupts or replaces these files, the Boot Manager may go missing.

How to perform Windows Boot Manager missing from BIOS fix using PC?

To fix Windows Boot Manager missing from BIOS using PC, here we list some solutions to try.

Solution 1. Check hardware connections and disconnect all external devices

Open your computer case (if it's a desktop) or contact a professional technician to check and secure all hardware connections. Ensure that your hard drive or SSD is properly connected to the motherboard and that there are no loose connections. And you need to disconnect the external storage device, like a USB flash drive, floppy disk, or external hard drive, etc. If such like devices aren’t bootable, you will get Windows Boot Manager missing error.

Solution 2. Update BIOS/UEFI Firmware

Step 1. Identify Your Motherboard/PC Manufacturer and Model: Press the Windows key + R on your keyboard to open the Run dialog box. Now, type msinfo32 and press Enter.

In the System Information window that opens, look for the "System Manufacturer" and "System Model" entries. Note down this information, as it will help you find the correct BIOS/UEFI update.

Step 2. Download the BIOS/UEFI Update: Visit the official website of your motherboard/PC manufacturer. Look for the support or downloads section on their website.

Then, search for the BIOS/UEFI update based on your system model and download the latest version available. Ensure that you download the correct update, as using an incorrect one can damage your system.

Now, you need to ensure that your laptop or PC is connected to a stable power source during the entire update process. A sudden power loss during the update can cause severe damage. Close all open applications to avoid any interference during the update.

Disable any antivirus software temporarily to prevent it from interfering with the update process.

Step 3. Locate the downloaded BIOS/UEFI update file. It is usually a .exe or .iso file. If it is a .exe file, double-click on it to run the update. If it is a .iso file, you'll need to create a bootable USB drive to update from it.

Step 4. When you run the BIOS/UEFI update, follow the on-screen instructions carefully. Read any warnings or prompts that appear during the update process. The update process may take a few minutes. Do not interrupt or turn off your PC during this time.

Step 5. Reboot your PC to check the error is solved or not.

Solution 3. Rebuild the BCD & MBR using Command Prompt

Step 1. Insert the Windows installation media (DVD/USB) and boot from it.

Step 2. Select your language preferences and click "Next."

Step 3. Click on "Repair your computer" > "Troubleshoot" > "Advanced options" > "Command Prompt."

Step 4. In the Command Prompt, type the following commands one by one, pressing Enter after each:

• bootrec /fixmbr
• bootrec /fixboot
• bootrec /scanos
• bootrec /rebuildbcd

Solution 4. Change boot order or boot device priority

You can also change boot order and boot device priority on your PC to fix Windows Boot Manager missing. If you can’t enter BIOS to perform this work, then here we recommend you AOMEI Partition Assistant Professional, a disk and PC manager that is compatible with Windows 11/10/8/8.1/7 PC and all brands.

You can create a bootable media with Partition Assistant on another computer and then boot into this tool to use the “UEFI BIOS Boot Options Manager” function to easily change boot order.

Step 1. Install and run this tool on another PC, and create a bootable media.

Step 2. After you boot from this USB, you can enter the tool to use “UEFI BIOS Boot Options Manager” function.

Step 3. In the pop window, you can click a boot option and click the button up and down to change the boot sequence of your computers.

Or you can delete the not available or unnecessary boot option.

After you finished your setting, you can click “Restart Now” to reboot PC.

To sum up

Dealing with a missing Windows Boot Manager can be frustrating, but by understanding the potential causes and implementing the appropriate solutions, you can overcome this issue. With AOMEI Partition Assistant, you can stay proactive in maintaining your system to prevent such problems in the future.

Besides boot manager, this tool can also clone disk, , move installed apps without reinstalling, convert a disk to MBR/GPT without data loss, clean junk files, test disk speed, etc. What’s more, the Server edition and other advanced editions support Windows Server system and enterprise users.