Fix Damaged & Corrupted Master Boot Record (MBR)

More about Master Boot Record (MBR)

MBR is always located on the first sector of the disk and created automatically once the disk has been initialized/partition is created. It is further divided into three parts which are Boot Loader, Partition Table and Magic Number. Total bytes contained by MBR are 512 out which Boot Loader contains 446 bytes, Partition table contains 64 bytes and remaining 2 bytes are for Magic Number.

Boot Loader: Whenever you turn your computer, boot loader is the program which will load your operating system. It contains an executable code for the boot start.

Partition Table: It keeps a record of the partition information of your local disk.

Magic Number: It is the signature word for the sector which shows device as a valid bootable device. It should always be 0x55AA/ 0xAA55.

Causes of damage to Master Boot Record

It had been found many times that due to improper shutdown, power outage, malware attack and other inappropriate operations like deleting the partition that contains the system results in damaging MBR. This will in turn not allow you to load your operating system on your computer when you start it and different errors will be displayed which are given below.

Errors Generated

• Operating System not found.
• Operating System missing.
• Error loading Operating System.
• Invalid partition table.
• No bootable medium found
• Blank black screen
• Reboot and Select proper boot device or Insert Boot media in selected boot device and press a key.

Methods to fix Damaged & Corrupted Master Boot Record

There are few manual methods which could be followed to repair damaged MBR. These are described below in detail:

1. Use FDISK command for MS DOS, Windows 95, 98 and ME: In case you are using DOS, Windows 95, 98 or ME operating system then the simplest method to repair damaged MBR is by running Microsoft’s DOS utility FDISK with MBR parameter. Syntax to run this command is A:\> FDISK.EXE /MBR
2. Fix MBR with Recovery Console: If you have the original Windows setup in USB, CD-ROM or Floppy disk then you can follow these steps to fix damaged MBR:
   1. Insert your original bootable CD in your system.
   2. As the Welcome screen appears, click on ‘Repair your computer’ option which is available down at the left-hand.
   3. Now go to ‘Troubleshoot’ option.
   4. In ‘Troubleshoot’ option click on the ‘Advanced Options’.
   5. A list of option will appear out of which select the ‘Command Prompt’.
   6. Type the following command, when your Command Prompt window loads: BOOTREC /FIXMBR > BOOTREC /FIXBOOT > BOOTREC /SCANOS > BOOTREC /REBUILDBCD. Note: Here ‘>’ denotes that you press ‘Enter’ after each step. Wait till each step gets completed.
   7. Once the process is completed, remove the CD from system.
   8. Now type ‘EXIT’ and then press ‘Enter’.
   9. Restart the computer to check if the problem still persists.

Fixing Error using Bootrec

1. Boot the system using recovery disc or system repair disc
2. Once the system is booted, navigate to Troubleshoot > Advanced options > Command Prompt > and then execute this command – bootrec.exe /fixmbr
3. Run the command exe as required
   1. bootrec.exe/fixmbr to repair damaged MBR
   2. bootrec.exe/fixboot to write new boot sector
   3. bootrec.exe/rebuildbcd to rebuild boot configuration data
   4. bootrec.exe/scanos to scan the operating system and adding any missing windows configuration
4. Restart the system as the boot gets complete

Limitations of Manual Tricks or Solutions

Although these methods prove beneficial in repairing your Damaged & Corrupted Master Boot Record but it is not guaranteed all the time. These methods also require good technical knowledge of DOS and hence novice users may find themselves in doubtful situation while using them. So, in order to completely repair your MBR, it is recommended to go for third-party professional tools.

There are various tools available which can be used to fix this kind of corruption in your MBR. One of the most renowned is Windows data recovery tool that can retrieve the files which are lost due to damaged hard drive partitions. One can also create an image of hard disk for backup purpose with this tool. The tool is created to support data recovery from Windows 10, 8, 7, Vista, XP and 2000.

Final Words

Corruption in Master Boot Record (MBR) of Windows system leads to many booting errors and result in failure in normal system booting. There are inbuilt repair facilities to fix corrupted or damaged MBR like using recovery consoles or BootRec command depending on the success of the process. All these methods are quite technical and not for all users. That is why advanced software is suggested to fix and recover Windows data efficiently that got corrupted due to such errors.