Windows 8 MBR fix

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What is MBR

MBR is the master boot record of a hard disk. It is created on the first partition when you first install Windows. MBR consists of three parts, i.e. Boot Loader, Partition Table and Magic Number.

Boot loader is a program that loads an operating system when a computer is turned on. Partition table records partition information on local disks. Magic number(0xAA55/0x55AA) marks the device as a valid bootable media.

An invalid magic number indicates a corrupted or missing MBR. Master Boot Sector contains 512 bytes in total, of which the boot loader takes up 446 bytes, partition table 64 bytes, and magic number 2 bytes. If the MBR is damaged, you won’t be able to boot into Windows.


Nessity to Repair MBR in Windows 8

Why fix MBR in Windows 8? Obviously, this is due to MBR damage. And this damaged can be caused by virus attack, power outage and improper operations like listed below:

MBR fix

As we have mentioned, if the master boot record is broken, your computer will fail to boot and show you some of the following errors:

1.”Error loading operating system_”
2.”Operating System not found_” or “Operating System missing_”
3.”Invalid partition table_”
4.”Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key_”

In this situation, you have to roll up your sleeve and find a way to fix MBR in Windows 8.

Two Ways to Fix MBR in Windows 8

Normally, there are two ways to repair MBR. Follow the instructions below to repair master boot record by yourself.

1. Fix MBR with command prompt and installation DVD
Fix MBR with command prompt requires the original Windows 8 or 8.1 installation DVD. The instructions are:
1.Boot from the original installation DVD.
2.At the Welcome screen, click “Repair your computer”.

windows 8 repair screen

3.Choose” Troubleshoot > Advanced options > Command Prompt”.

advanced options in windows 10

4.When the Command Prompt loads, type the following commands in order: “bootrec /FixMbr > bootrec /FixBoot > bootrec /ScanOs > bootrec /RebuildBcd”. Remember to press “Enter” after each command and wait for each operation to finish.
5.Remove the DVD from the disk tray.
6.Type exit and Hit “Enter”.
7.Restart your computer and check if Windows 8/8.1 can boot now.

  1. Fix MBR without CD
    Another feasible method is by using third-party software to repair MBR without CD. Currently, There is lots of partition software in the market that can achieve this goal, and MiniTool Partition Wizard Bootable CD is among the most reliable ones. In addition, no professional knowledge is required, and only three steps are needed. Next, we will show users the detailed steps. 

MiniTool Partition Wizard Bootable CD Helps to Fix MBR in Windows 8 without CD

Step 1: Users need to  download MiniTool Partition Wizard Bootable CD (Pwfree91.iso file) and burn the iso file to a USB drive with burning software. After that, connect boot flash drive with computer to start the very computer.

Step 2: Set computer to boot from the bootable media. Press “+” “-” to move the target hard drive to the first place and then press F10 to save settings.

bios setup

Soon you will see the following interface. Users should select “Boot from Partition Wizard Boot Disc” rather than “Boot from Local Drive”: 

parition wizard boot disc

Step 3: After successful boot, users will see the main window of MiniTool Partition Wizard, where all disks and partitions are shown. To fix MBR for Windows 8, users need to select the target disk and choose the function “Rebuild MBR“. At last, click on the icon “Apply” to execute changes.

rebuild mbr with minitool partition wizard

After these operation, we can say the work to repair MBR in Windows 8 is finished. Now you can remove the bootable media and set your computer to boot from the system disk.


In a word, MBR damage can cause system boot failure. If you are prompted or need to fix mbr in Windows 8, 7, Vista, XP, and even Windows Server, turn to the partition tool – MiniTool Partition Wizard Bootable CD. It is totally FREE and we believe it can meet most users’ demands.

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