How to Fix MBR on External Drive in Windows 8: A Step-by-Step Guide

MBR (Master Boot Record) involves a partition table for the disk and an executable code for the boot start. MBR locates on the first sector of the disk, and it will create when the first partition of the hard drive is created. If your MBR is corrupted, your system will not boot due to the Windows Inaccessibility to the drive. In this case, you will confront some errors such as “Invalid Partition Table”, “Operating System Not Found”, and “Missing Operating System”.
When your MBR is corrupted on an external USB drive or hard drive, you will not have any access to the disk’s partition. Because the partition table of your disk is damaged. Thus, your drive’s data will be lost you cannot use your drive to do something new on it.
In this article, we describe how to fix MBR on External Drive in Windows 8. To learn more, follow us till the end of this article.
What Causes External Drive MBR Corruption?
All the MBR errors seem the same in both internal and external drives. Generally, there are three main possible reasons for external hard drive master boot record corruption. Here is a list of these main possible reasons:
- MBR overwritten: Sometimes, when some programs are installed on the external drive, may accidentally write part of the MBR.
- Virus infection: When your hard drive gets infected by viruses, the MBR sector is the first part that the virus decides to infect. To lower this risk, you can lock the MBR part, so there will be no access to any data on that drive.
- Hard drive failure: A damaged cluster of hard drives can make MBR unreadable.
- Incorrect shutdown: If you shut down your PC without separating the external drive, you will harm the MBR sector.
How to Fix MBR in Windows 8?
Here, we described three methods to fix a Master Boot Record of the inaccessible external hard drive. To do so, follow the steps mentioned below:
Note: If you have any important data on your external drive that needs to be recovered, you should turn to professional data recovery software. Because all data will be lost on the external hard drive.
1. Fix MBR on External Drive by Using Windows Installation Disc
- First of all, you need to plug in your external disk to your PC. Shut down your PC and insert the installation disk, then boot from the disc.
- Choose time, language, and keyboard input. Then, click Next.
- Now, select the Repair your computer option from the lower-left corner.
- To open Command Prompt, hold Shift + F10 hotkey.
- On the Command Prompt Window, type the letter of your external hard drive partition, like F:, with a colon.
- Hit Enter.
- Copy and paste these commands one after another, then hit the Enter key.
- bootrec.exe /fixmbr
- bootrec.exe /fixboot
- bootrec.exe /rebuildbcd
8. Then, restart your PC.
Note: You will need to change boot priority to the installation disc in BIOS if your Windows falls to the internal disk.
Note: If the Shift + F10 hotkey did not work, you would need to try this approach with the installation disc:
- In Windows 10: Follow this direction to open Command Prompt.
- Select an option
- Troubleshoot
- Command Prompt
- In Windows 7: Follow this direction to open Command Prompt.
- Next
- System Recovery Option
- Command Prompt
2. Fix MBR on External Drive by Using Advanced Options
This method is awesome if you do not have a repair disc or Windows installation disc. To fix MBR with this method, follow these steps:
Windows 10 users:
- Open Setting.
- Go to the Update & Security section.
- Select Recovery.
- Click on Restart now.
- Select an option.
- Click Troubleshoot.
- Go to the Advanced options.
- Click on Command Prompt.
Windows 7 users:
- Restart your PC.
- While that, keep pressing F8 to open the repair interface automatically.
- Then, click on the Repair your computer option.
- Select Troubleshoot.
- Go to the Advanced options section.
- Click on Command Prompt.
Now, at the prompt, you need to follow steps 5 to 8 from the first method to rebuild your external hard drive’s MBR.
3. Fix MBR on External Drive by Using Freeware
Sometimes may the bootrec/fixmbr command disappoint you with some errors such as “File not found”, “Access denied”, “Element not found” and “I/O device error”.
These two above methods are advanced command line operations, and they might not be suitable and easy to use for all users. There is an app called, AOMEI Partition Assistant Standard, which is a free partition manager. This app lets you rebuild the MBR of your external drive in GUI (graphical user interface)
Note: You do not need to restart your PC to fix the MBR.
To fix MBR on an external drive via freeware, follow these steps:
1.Plug in your external drive to your computer.
2.Download, install, and launch AOMEI Partition Assistant.
3.Right-click on the external disk and choose the Rebuild MBR option.

4.Now, you need to choose the type of MBR for your current OS (operating system).

5.Select the Apply option from the corner-left upper side of your screen.
6.Then, click on the Proceed button to execute the pending operations.

7.Choose Yes from the pop-up window.
Note: If you do not want to boot your Windows to repair MBR, you can create a bootable media and perform the fix in WinPE mode.
Note: If you want to fix the MBR on the server, you can use the AOMEI Assistant Server.
The Bottom Line
When the MBR of your external hard drive or external USB drive, you can repair the MBR via Advanced options of Windows, Windows Installation, and the professional partition table repair tool.
In this article, we suggested three methods to fix the Master Boot Record (MBR) on the external drive in Windows 8. Which methods do you prefer? Do you know any other methods to fix MBR in Windows 8? Share your opinion with us.