How to Fix or Solve MBR (Master Boot Record) Issues in Windows 11/10/8/7/Vista/XP

Updated by

Tracy King 

Written by

Linda 

Last updated on April 22, 2024

Are you looking for ways to fix the MBR in Windows 10/8/7? On this page, we'll introduce you to what MBR is, the causes and symptoms of a corrupted MBR, and how to repair it with practical solutions.

See the Fixing the MBR section for instructions on how to repair a damaged MBR and get your computer booting normally again.

Note: The below troubleshooting solutions only work for MBR disks on Windows PCs. If your operating system disk is GPT, please turn to Repair EFI Bootloader in Windows 10/8/7 for assistance.

How to fix a damaged MBR? Here, we'll provide a safe and reliable method to assist you. Just follow these steps.

What is MBR?

The Master Boot Record, also known as the Master Partition Table or Partition Sector, is a boot sector (an area on a hard disk) that contains information about the partitions of a disk and serves as a loader for the operating system that runs on it.

The MBR is created by the MBR generator when you first install Windows on an MBR disk. It's the first 512 bytes of the hard drive, as shown in the image below.

An MBR partition contains two important components:

• Master Boot Record code
• Disk Partition Table

Working together, these two components transfer control to the boot sector of that partition, which continues the startup process and helps the Windows operating system start successfully.

Read more: What is MBR Disk.

What happens if the MBR is corrupted?

In this section, you will learn how to:

1. Reasons for a damaged boot sector
2. What happens if the boot sector is damaged
3. When and how to repair the MBR (Master Boot Record)

Most often, an MBR is damaged or missing due to improper removal, power failure, or a virus infection.

What happens if the MBR is damaged? A damaged MBR can prevent you from accessing your operating system, showing an error message like "Operating System not found," or simply a black screen with no prompt.

So, what are the signs of a corrupted MBR?

If you see any of the following error messages when starting up your computer, it means that the MBR on your computer is corrupted:

1. Operating system failed to load. 2. Operating system not found. 3. Invalid partition table. 4. No bootable medium found. 5. Restart and select the correct boot device.

If any of these symptoms sound familiar, don't worry.

You can immediately fix the corrupted MBR and allow your computer to boot normally by following the repair methods shown in the sections below.

Method 1: Fix MBR in Windows 11/10/8/7 with Partition Master Tool

Applies to: Windows 11, 10, 8.1, 8, 7, XP, Vista; Windows 2000, Windows Server 2012.

Instead of manual fixing, a tool – Partition Software Partition Master offers you the easiest way to solve MBR problems. It has a feature called “Rebuild MBR”. Once MBR (Master Boot Record) is corrupted, you can simply apply this feature to fix the master boot record without damaging the partition table.

There are two methods to fix MBR with Partition Master tool:

1. Connect the MBR hard drive to another functioning computer for repair. 2. Create a WinPE bootable disk suitable for all Windows OS so the computer can boot up.

If you have a spare computer, you can skip ahead to the second method to use a guide. If not, follow the steps below to repair the damaged MBR on your own:

Step 1. Create a bootable WinPE disk

1. Launch AOMEI Partition Assistant, and click "Create Bootable Media" on the toolbar. Choose "Create a bootable CD/DVD". 2. Click "Next" to finish the process.

Create a bootable disk

Step 2. Boot into the Partition Master Live USB

Plug in the bootable USB or CD/DVD to your computer. Restart your computer and press F2 or Del to enter BIOS. Set it to boot from “Removable Device” or “CD-ROM Drive”. The Partition Master will then launch automatically.

Step 3: Rebuild the MBR

Click on “Toolbox” and then select “Rebuild MBR”.

The next sentence only needs to be translated into American English:

Select the disk and MBR type, then click “Rebuild”.

You'll then see a message that says, "The MBR of Disk X has been successfully rebuilt."

## Method 2: Fix the MBR Using Command Prompt on Windows 10/8/7/Vista/XP

Applies to: Manually fix MBR corruption issues on Windows 10/8/7, Vista, etc.

When the MBR on a Windows computer becomes corrupted, you can manually repair it using the Command Prompt. The steps vary slightly depending on which version of Windows you're using.

Now select the appropriate solution to fix MBR on your Windows PC:

• #1. Fix MBR on Windows 10
• #2. Fix MBR on Windows 8.1/8
• #3. Fix MBR on Windows 7
• #4. Fix MBR on Windows Vista
• #5. Fix MBR on Windows XP

Repair the MBR in Windows 10 via CMD

For a visual guide on how to fix the MBR, you can watch this video, starting from 0:25:

Step-by-step Guide: Opening Command Prompt in Windows 10 to Repair MBR 1. First, press the "Win + X" keys on your keyboard, which will open a Quick Access menu. 2. In the Quick Access menu, choose "Command Prompt (Admin)" or "Windows PowerShell (Admin)." If you're using Windows 11, you might need to select "Windows Terminal (Admin)." 3. If prompted for permission, click "Yes" or enter your administrator password to proceed. 4. In the opened Command Prompt window, type the following command to repair the Master Boot Record (MBR): ``` bootrec /fixmbr ``` 5. Press the "Enter" key to execute the command. This will run a program to fix or replace a damaged MBR. 6. If the command executes successfully, you might see a message indicating that the MBR has been successfully repaired. If there are no error messages, you can proceed to the next step. 7. Close the Command Prompt window and restart your computer. This will apply the MBR changes and boot the system. Before attempting this, make sure you have backed up important data, as incorrect actions could result in data loss or an inability to start the system. If unsure, it's advisable to seek professional assistance.

Step 1: Boot the PC from the original Windows installation DVD (or recovery USB drive).

Step 2: On the Install screen, click Repair your computer.

Step 3: Click on Troubleshoot > Advanced options > Command Prompt.

Step 4. Type each of the following lines at the command prompt, pressing Enter after each:

• bootrec /fixmbr
• bootrec /fixboot
• bootrec /scanos
• bootrec /rebuildbcd
These are commands used in the Windows Recovery Environment (WinRE) Command Prompt to troubleshoot and fix boot-related issues. Here's a brief explanation of each command: 1. **bootrec /fixmbr**: This command replaces the Master Boot Record (MBR) without overwriting the partition table. It's used when the MBR is corrupted or infected by malware. 2. **bootrec /fixboot**: This command writes a new boot sector to the system reserved partition or the active partition. It's used when the boot sector becomes damaged or missing. 3. **bootrec /scanos**: This command scans all disks for valid Windows installations and adds them to the Boot Configuration Data (BCD) store. It's helpful when Windows installations are not showing up in the boot menu. 4. **bootrec /rebuildbcd**: This command searches for all valid Windows installations and allows you to重建 Boot Configuration Data (BCD) store. It's typically used when the BCD store is corrupted or missing, preventing the system from booting properly.

5. After completing the steps, type exit to close the Command Prompt, and then restart your Windows 10 device.

Alright, you should be able to successfully boot up Windows 10 now.

Repair the MBR in Windows 8.1/8 using Command Prompt

Step 1. Boot from the Windows installation DVD or recovery USB.

Step 2: On the setup screen, choose the option to repair your computer.

Step 3. Go to Troubleshoot > Command Prompt.

Step 4. Type the following commands, pressing Enter after each:

• bootrec /fixmbr
• bootrec /fixboot
• bootrec /scanos
• bootrec /rebuildbcd
These are commands used in the Windows Recovery Environment (Windows RE) to troubleshoot and repair boot issues. Here's a brief explanation of each command: 1. **bootrec /fixmbr**: This command replaces the Master Boot Record (MBR) without overwriting the partition table. The MBR is responsible for loading the operating system when the computer starts. 2. **bootrec /fixboot**: This command writes a new boot sector to the system partition. The boot sector contains the code necessary to start the Windows loader. 3. **bootrec /scanos**: This command scans all disks for installed Windows installations and adds any missing entries to the Boot Configuration Data (BCD) store. 4. **bootrec /rebuildbcd**: This command searches for all Windows installations on the computer and allows you to select which ones to add to the BCD store. It's useful when the BCD store becomes corrupted or if you've recently added or removed operating systems. Remember to run these commands in the Command Prompt with administrative privileges in the Windows RE environment.

Step 5: Type exit, then restart your computer.

Your Windows 8 computer should now boot normally. Occasionally, you might see the “Access is denied for Bootrec /fixboot” error. Don't worry; there's a fix for that:

Got 'Access is Denied' Error with Bootrec/Fixboot? Solutions Here

What to do when you get the "bootrec /fixboot access is denied" error message in CMD? This post offers all possible solutions to fix the '[bootrec /fixboot] Access is Denied' issue in Windows 10/8/7.

Repair the MBR in Windows 7 with CMD

Step 1: Boot from the Windows 7 installation DVD.

Step 2: Press any key to boot from the DVD.

Step 3: Choose a language and keyboard layout, then click "Next."

Step 4: Select your "Operating System" and click "Next".

Make sure the checkbox for “Use a recovery tool that can fix Windows startup problems” is checked.

Step 5: On the System Recovery Options screen, click Command Prompt.

Step 6: Type each of the following lines and press Enter after each one:

• bootrec /fixmbr
• bootrec /fixboot
• bootrec /rebuildbcd
These are commands used in the Windows Recovery Environment (WinRE) Command Prompt to troubleshoot and fix boot-related issues. Here's a brief explanation of each: 1. **bootrec /fixmbr**: This command replaces the Master Boot Record (MBR) without overwriting the partition table. The MBR is responsible for loading the boot loader, so if it's corrupted or damaged, this command can help repair it. 2. **bootrec /fixboot**: This command writes a new boot sector to the active system partition. If the boot sector becomes corrupted, this command can help restore it, allowing the system to boot correctly. 3. **bootrec /rebuildbcd**: This command scans all hard disks for Windows installations and recreates the Boot Configuration Data (BCD) store. The BCD store contains information about bootable operating systems on your computer. If the BCD store is damaged or missing, this command can help recover it and ensure that Windows can boot properly.

Step 7: Type exit to close the window and restart your computer.

You can now access files and apps on the Windows 7 computer again.

Repair the MBR in Windows Vista

Step one: Boot from the Windows Vista installation CD or DVD.

Step 2: Choose a language and keyboard layout, then click "Next".

Step 3: In the setup screen, click on “Repair your computer.”

Step 4: Select your "Operating System" and click "Next".

5. When the System Recovery Options appear, click Command Prompt.

Step 6: Type each of the following lines, pressing Enter after you type each one:

• bootrec.exe /fixmbr
• bootrec.exe /fixboot
• bootrec.exe /rebuildbcd
These are commands used in the Windows operating system to troubleshoot and repair the boot sector. Here's a brief explanation of each: 1. **bootrec.exe /fixmbr**: This command repairs or replaces the Master Boot Record (MBR) without affecting any partitions. The MBR is responsible for loading the boot loader. 2. **bootrec.exe /fixboot**: This command writes a new boot sector to the system partition. It's used when the boot sector becomes corrupted or damaged. 3. **bootrec.exe /rebuildbcd**: This command scans all disks for Windows installations and recreates the Boot Configuration Data (BCD) store. The BCD stores information about how and where Windows should boot. Remember, these commands are typically run from the Windows Recovery Environment (WinRE) or a Windows installation media in the Command Prompt.

Step 7: Type exit and press Enter to close the window.

Once Windows 7 has restarted, you should be able to use all of your computer's functions again.

Repair the MBR in Windows XP

Step 1: Boot from the Windows XP installation CD.

Step 2: From the welcome screen, open the Recovery Console.

Step 3: Type 1 and press Enter.

Step 4: Press Enter after typing your password.

Step 5: Type fixmbr and press Enter.

Step 6: Type Y and press Enter.

Step 7: Type exit, then press Enter.

Then, restart your Windows XP computer, and it should boot up normally.

Conclusions

In this article, we explain what MBR is, what happens when the MBR is damaged, and when you need to fix it. We also gather 2 practical methods to repair MBR in Windows 10/8/7/Vista/XP.

For the easiest solution, try using the disk partition tool Partition Master, which can quickly and efficiently fix the MBR so that your computer can boot up again.

FAQ: How to Fix Common MBR Issues

1. What is MBR Recovery?

Rebuilding the MBR involves repairing a damaged MBR partition table and restoring the master boot code, so that the computer can load and start the Windows operating system again.

Reinstalling Windows will also fix this problem, but that can be inconvenient – even daunting – for those unfamiliar with the operating system. By comparison, rebuilding the MBR is simpler and quicker.

"Partition Master" has the feature to rebuild MBR, so it can easily help you fix a damaged MBR with just a few clicks.

2. Will deleting MBR delete data?

If the MBR is deleted, the entire hard drive and its data become inaccessible. Usually, you can't access or view it directly in Windows File Explorer or Disk Management. Also, modifications or any changes to it are not allowed to keep the operating system bootable.

3. Where is the Master Boot Record (MBR)?

The Master Boot Record (MBR) is created on your first partition when you first install Windows. The MBR is the first 512-byte sector on a hard drive.

4. How to Fix MBR Error: Bootmgr is Missing

Here are some quick solutions to try and fix the “BOOTMGR is missing” error:

< li > Restart your computer < /li >< br /> < li > Reset all internal data and power cables < /li >< br /> < li > Remove all removable media < /li >< br /> < li > Change the boot order in BIOS < /li >< br /> < li > Copy or recreate the BCD files < /li >< br /> < li > Repair the corrupted MBR < /li >

For detailed steps, refer to Fix BOOTMGR is Missing in Windows 10/8/7 for assistance.

How to Fix MBR Error: Operating System Not Found

Try the troubleshooting steps listed below to get your computer past the "Operating System Not Found" error and back up and running:

• Check the BIOS
• Restart from a bootable disk
• Set BIOS to default settings
• Rebuild MBR using CMD or a partition manager software
• Set the correct active partition

For a step-by-step guide, see How to Fix 'Operating System Not Found' or 'Missing Operating System' Error in Windows.