By Emily / Last Updated August 23, 2019


“I have a 1TB Seagate external hard drive that is damaged and I recently ran a scan with the HDD regenerator and it told me that the Master Boot Record is damaged. Anyone know any great MBR repair tool for external hard drive? Thanks a lot!”

Importance of MBR on external or internal hard drive

MBR is a boot sector of your hard disk that contains the important information about the partitions on your hard drive and loads the OS. MBR is created on the very first partition when you first install Windows. It’s the first 512 bytes of your hard disk.

Therefore, when the MBR on your external hard drive gets damaged, you might be unable to access the external hard drive. If the internal hard drive MBR is corrupted, the Windows cannot boot successfully with popping out meet various Windows boot failure error messages like “Error loading operating system” “Operating System not found”, “Invalid partition table” , “No bootable medium found”, “Reboot and select proper boot device”,etc.

So learn how to repair damaged MBR on external hard drive or internal hard drive is quite necessary for ensuring your computer functioning well.

Why MBR gets damaged on (external) hard drive?

Before learning how to fix MBR on hard drive, you might want to know what can cause the MBR damage of external or internal hard drive, so as to prevent possible MBR corruption in future. Generally speaking, there are three main causes for damaged MBR either on external hard drive or internal hard drive:

  • A virus infection: when a virus is loaded onto your computer, the MBR will become its prior target to infect since master boot record is the most important part of your hard drive.

  • A drive failure: if there are some defective clusters on the area where the MBR is located on the hard drive, the master boot record is more likely to become unreadable.

  • MBR overwrite: if the master boot record is overwritten by some programs accidentally, it will become damaged as well.

Best Free MBR repair tool for external hard drive-AOMEI Partition Assistant

Now, back to the point- is there any professional MBR repair tool to fix damaged master boot record? Actually, when you Google online, many free MBR repair tools will come into your sight. To save your time, here we would like to recommend AOMEI Partition Assistant Standard. This free MBR repair tool comes with a feature named Rebuild MBR, which could help you easily and quickly rebuild the corrupted MBR of both external and internal hard drive in Windows 7/8/10/XP/Vista.

Best Free MBR Repair Tool For External Hard Drive| AOMEI Partition Assistant

This MBR repair tool can work well on fixing damaged MBR on both external and internal hard drive in simple steps. More »

Download Freeware

Win 10/8.1/8/7/XP

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Now free download the powerful MBR repair software and learn how to repair damaged MBR on external hard drive.

Step 1. Install and run AOMEI Partition Assistant Standard on your Windows computer, right click the external hard drive and select Rebuild MBR.

Rebuild Data Disk MBR

Step 2. Select the type of MBR for your current operating system.

Choose MBR Type

Step 3. Click Apply->Proceed to execute the pending operations.


Attention: If the corrupted MBR has caused your Windows unable to boot normally, you can also use AOMEI Partition Assistant Standard to make a bootable USB stick to access the currently non-bootable operating system. Then take the same step above fix MBR on hard drive in the WinPE environment.

Make Bootable Media

Fix the damaged MBR on external hard drive using CMD

Besides using a professional MBR repair utility, another popular MBR repair solution is running the “bootrec.exe/fixmbr command” in the Command Prompt window. This always requires Windows system repair or installation disc.

Step 1. Put the Windows installation DVD into the disk tray and boot your computer from it.

Step 2. Follow the wizard to choose “Repair your computer”> “Troubleshoot” > “Advanced” > “Command Prompt” (Windows 8/8.1/10). In Windows 7, select “Next” after choosing the operating system, in the System Recovery Options window, click on “Command Prompt”.

Step 3. When the Command Prompt loads, type the drive letter of the external device, followed by a colon like E:, into the prompt. Press Enter. Then execute the following commands in sequence:

  • bootrec /FixMbr

  • bootrec /FixBoot

  • bootrec /ScanOs

  • bootrec /RebuildBcd

However, it might not be considered as a wise choice for the common computer users without enough IT knowledge.


No matter you want to fix MBR via a MBR repair tool for external hard drive or using Command Prompt in Windows 7/8/10, above content can help you a lot. If you need to repair MBR on Windows Server computer, you can try AOMEI Partition Assistant Server version.