Master Boot Record
The Master Boot Record (MBR), often known as the “master partition table” or “partition sector,” is the most critical piece of data that allows a computer to locate and identify the operating system, allowing Windows 10 to boot. It stores information about the hard drive’s partitions and serves as a loader for the operating system you’re using.
The Master boot record gets created on the first partition you build when you install Windows. It’s your hard disk’s first 512 bytes. You cannot boot into Windows if the MBR gets broken. MBR gets used by all Windows versions, and if it gets destroyed, you will be unable to boot.
It can get harmed by viruses that target the MBR and attempt to replace it with their software or by dual booting with a Linux distribution. Viruses and other types of malware can destroy the Master Boot Record if system settings are changed, the computer shuts down erroneously. You may also receive the error message, which prevents the device from booting up.
If this happens, you’ll need to use an install DVD and a few Command Prompt lines to fix the MBR and get Windows 10 to load again.
For Windows 7,8,10 and 11, the procedure is nearly identical. To begin, you’ll need a Windows installation DVD. It is tough to move forward without it.
- To access the Windows Recovery Menu, press F8 when booting up.
- Select Troubleshoot from the drop-down menu.
- To access the Automatic Repair menu, go to Advanced settings.
- We must use the Bootrec.exe program. Then, one after another, enter the commands below into the command prompt:
- Exit the program and restart your computer. You may need to perform some more commands in some circumstances.
It’s a good idea to back up MBR or build a System Recovery Disk so that you don’t have to search for the Windows Recovery Disk if something like this happens.
Follow these procedures to build a system recovery disc in Windows:
- Press Win + R and type RecoveryDrive.exe into the search box.
- Next should get selected.
- It will begin building the Recovery for your USB drive as soon as you insert it.
Alternative Method To Repair MBR
Follow these procedures to fix MBR issues on a Windows 10 computer:
- Generate a Windows 10 bootable USB disc.
- To start from the bootable media, change the device firmware settings.
To modify the settings for the Basic Input Output System (BIOS) or the Unified Extensible Firmware Interface (UEFI), use one of the function keys (F1, F2, F3, F10, or F12), ESC, or Delete. However, the procedure varies depending on the manufacturer and model of the gadget. More detailed instructions can get found on your manufacturer’s support website.
- The bootable disc should get used to starting the computer.
- In the Windows 10 Setup, click the Next button.
- In the lower-left corner, click the Repair your computer icon.
- Select Troubleshoot from the drop-down menu.
- Under the drop-down box, choose the Advanced settings option.
- Select Command Prompt from the drop-down menu.
You’ll now be in the Command Prompt environment, where you may use the Bootrec.exe utility to repair the Master Boot Record on your Windows 10 computer. Depending on your situation, the Bootrec.exe command utility offers a variety of alternatives.
- When you need to repair MBR corruption issues or clean the code from the MBR, use the FixMbr option. This Bootrec /fixMbr command will not overwrite the hard drive’s existing partition table.
- When the boot sector gets changed with non-standard code, the boot sector gets damaged, or you installed an older version of the operating system alongside a more recent one, use the FixBoot option.
- When the Boot Manager menu does not show all of the operating systems installed on the device, use the ScanOS option. This Bootrec /ScanOS option scans all discs for compatible installs and displays any entries not found in the BCD store.
- When you don’t have any other options and need to rebuild the BCD (Boot Configuration Data) store, use RebuildBcd.
If investigating the “Bootmgr Is Missing” error and rebuilding the BCD store does not resolve the issue, use the following instructions to export and wipe the BCD store before reinstalling Windows 10.
Type the following commands at the Command Prompt while in the recovery environment and hit Enter on each line:
BCDedit /export C:\BCD_Backup
Attrib BCD -s -h -r
Ren C:\boot\bcd bcd.old
To add Windows 10 to the list of bootable operating systems on your device, press Y.
Command Prompt should be closed.
After you’ve completed the procedures, restart your computer, and Windows 10 should load normally again.
If you’re not sure what’s wrong with your computer, try all of the commands in to see if any of them fix the problem and let you boot into Windows 10.
While the “bootrec” command-line tool should be sufficient to restore the Master Boot Record, other associated issues may necessitate the use of additional command-line tools, which are outside the scope of this instruction.
How to Move MBR To Another Drive
Windows do provide a method for moving the boot file to a different location. You may also want to take a chance on it.
- Press the Start button and type the command prompt into the search box. Choose Run as administrator by right-clicking the Command Prompt software from the list.
- Type bcdboot c:\windows /s c: at the prompt and press Enter. Ascertain that you want to boot from the C drive. If it isn’t the correct drive letter, update it. Wait for the procedure to finish.
- Verify that the MBR has got successfully copied to another disc. Please keep in mind that the drive must be operational.
However, some users find that shifting MBR from one disc to another is extremely difficult, especially when it gets mounted as a separate drive on the disc. In that scenario, it gets recommended that you replicate the MBR boot drive differently.