Fix Boot Manager Failed to Find OS Loader for Windows 7/8/10

Getting an error message stating that boot manager failed to find OS loader error code 0x490 and cannot boot into Windows? You will find several ways to fix it in Windows 7/8/10.


By Lucas / Updated on May 12, 2023

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Boot manager failed to find OS Loader

Yesterday, I updated my Windows 7 Home Premium SP1 64-bit laptop with 3 of the 4 latest optional updates. When I restarted the laptop, it opened Startup Repair which I thought was bit strange. Now every time I boot up the laptop it loads up Startup Repair and lists these error messages.

Root cause found:

Boot manager failed to find OS Loader.

Repair action: File repair

Result: Failed. Error Code = 0x490

Time taken = 5522ms

Repair action: Boot configuration data store repair

Result: Failed. Error code = 0x490

Time taken = 156ms

Any help would be appreciated, Thanks in advance.

Start Repair Boot Manager Failed to Find OS Loader

Why does Boot Manager fail to find the OS loader in Windows?

This error message indicates that Windows Startup Repair couldn’t find an intact BOOTMGR bootloader in the directory where it should be located. It means the computers boot loader is either missing or has been corrupted in some way. How do you we fix the missing OS loader error? Before we try to do this, we need to learn why it happens to stop it occurring again in the future. Here are some of the reasons why Windows Startup Repair and the Boot Manager fail to find the OS loader:

  • Non-conventional power cut (power cut/system crash)

  • Your system hard disk might be damaged physically.

  • Bootloader was deleted.

  • System disk was removed.

How do you fix boot manager error in Windows 7/8/10?

Don’t panic, if you find yourself trapped in a ‘boot manager failed to find the OS loader’ error cycle and keep receiving errors 0x490, 0x2, or 0x3. We will show you three sure fire solutions for fixing the errors.

Solution 1. Run System File Checker (built-in Windows tool)

System File Checker (SFC) will check your Windows 10, 8, and 7 installation for any corrupted, invalid, or deleted system files. In order to use SFC you will need a Window Installation disk.

1. Insert the Windows installation disc into your computer.

2. Restart your PC and boot it from the installation disc.

3. Select the language and keyboard options.

4. Select Repair your computer -> Troubleshoot -> Advanced options -> Command Prompt.

5. Enter the following commands to check for system files errors:

sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows (C: is the partition which holds your Windows 10, 8, or 7 installation, if you have installed Windows to a different partition you should use that partition letter).

Solution 2. Repair bad sector or errors on the system drive

If the system hard drive has bad sectors or errors, then the boot manager may produce the ‘fail to find OS loader’ error message. If you want to find and repair the bad sectors or errors on the system HDD, then you should use the following commands in Command Prompt:

chkdsk C: /f /r (where C: is the system partition)

You must check all partitions on the system hard disk to make sure that you find and repair all bad sectors or errors. Just replace C: with the corresponding drive letter for each partition.

Solution 3. Repair damaged MBR (Master Boot Record)

If you want to repair the MBR table of your disk, then there are two methods you can try: Windows Installation disk and AOMEI Partition Assistant  Professional Edition.

▸If you have a Windows installation disc, you can try this:

Access the Command Prompt using the Windows installation disk (refer to the solution 1) and enter the following commands:

  • bootrec.exe /fixmbr

  • bootrec.exe /fixboot

  • bootrec.exe /rebuildbcd

After you have finished running the commands, check to see if the boot manager ‘failed to find OS loader’ error has been fixed.

▸If you don’t have a Windows installation disc or you would prefer not to enter the commands manually, you could instead use AOMEI Partition Assistant Professional edition to fix the error:

1. Click the link for a Free download of AOMEI Partition Assistant Professional Demo, and run and install it on a working Windows PC with the same operating system as yours. Connect a USB drive that has at least 16GB capacity to the same Windows computer.

Free Download Win 11/10/8.1/8/7/XP
Secure Download

2. In the main window of Partition Assistant, select Make Bootable Media under Tools.

Make Bootable Media

3. Click Next and tick USB Boot Device to create a bootable USB drive.

Choose Usb Drive

4. Press Proceed to create the USB.

5. Boot your Windows 10, 8, or 7 computer that has the error from the bootable media device. AOMEI Partition Assistant Standard will appear on the desktop, run the program.

6. Right-click the system hard disk and choose Rebuild MBR.

Rebuild  MBR

7. Select the MBR type for your Windows operating system.

Choose Mbr Type

8. Press Apply to confirm the operation. The boot manager failed to find OS loader error should now be fixed.

Apart from rebuild MBR, this software allows you to check and repair hard disk errors with Surface Test or Check Partition feature.


Now we know how to fix the "Boot Manager failed to find OS loader error" using both Command Prompt and AOMEI Partition Assistant. It’s possible that you may encounter other issues when updating your system, common errors include BOOTMGR is missing, operating system not found, and ‘invalid system disk’. Luckily, AOMEI Partition assist has the ability to fixes these errors and many more!

Besides, AOMEI Partition Assistant is also able to migrate OS to SSD, clone hard disk, clone partition, convert disk between MBR and GPT without losing data. More advanced features and functions like converting dynamic disk to basic disk without deleting volumes, splitting partition, quick partitioning a hard disk are also povided. If you need a powerful solution for your servers then we recommend checking out the Server edition of AOMEI Partition Assistant.

Lucas · Staff Editor
I prefer peaceful and quiet life during vacation,but sometimes I watch football match if my favorite club performs brilliantly in that season. And I love reading, painting and calligraphy, thus I send my friends festival handwriting cards every year.