How to Fix MBR ( Master Boot Record ) Damages Using Fdisk Commands

Last Updated:-March 22, 2010
MBR (Master Boot Record ) is stored in the first sector (512-byte) of hard disk and contains a primary partition table, disk signature, and instructions for BIOS to boot the computer are stored. It is stored outside the partition. It is created while hard disk partition. Any damage to this area is fatal because it can even stop your PC from booting. Damages to Master Boot Record can happen due to improper installation of multiple Operating Systems, certain virus attack, and hard disk error. This tutorial explains the reasons for MBR damages and quick fix to it.

Possible Reasons for MBR Damage

  1. Possible Virus attack

    There is a special type of malware called MBR virus, with the capability to damage the Master Boot Record by replacing the original MBR with another one created by it. Original Master Boot Record sector will be moved to some other locations in the hard disk. These viruses can start with system boot-ups even before loading OS and escape from normal Anti Virus scanning.

  2. Hard Disk Drive error

  3. Improper installation of multiple OS

Ill Effects Of a Damaged MBR

In most cases, users will find difficulties with starting their computers in safe mode. They will either don't see safe mode option in the boot menu or safe booting fails. If the damage is big, your PC may not start at all. So it is very important to fix any corruption as soon as possible.

How to Recover Corrupted Master Boot Record

To recover this sector, we have some tools which operate in recovery mode. We cannot actually change the MBR while Windows is running. Those recovery commands are provided below.

  1. Fdisk /mbr

    The MS-DOS command Fdisk /mbr rewrites the MBR on the disk and it will resolve all corruptions. This command is useless if your computer is infected with MBR viruses because they will again reinfect the new Master Boot Record sector. Hardware specialists do not recommend this command to fix issues and they recommend another command. That is the next one.

  2. Fixmbr

    This command works in Recovery Console only. The command, fixmrb, provides us with an option to specify the location of master boot record. It helps to fix the mbr of devices other than the master boot device. The only downside I see is the requirement of Windows Disc while running this tool. If you use this tool to recover MBR of another device (not the master boot device), you must use the following format.

    fixmbr (device_name)

Steps to run Fixmbr on your computer

  • Restart PC

    Restart your computer with Windows CD, where DVD/CD drive is the primary boot device.

  • Recovery Console

    Press the R key to start the Recovery Console when it prompts.

  • In Recovery Console command prompt, type fixmbr and follow the instructions

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