How to Fix the MBR (Master Boot Record) in Windows 10

Those of you experienced in Windows will probably have experienced errors in the MBR (Master Boot Record) at some point. It’s not a nice feeling, as Windows fails to boot, and you’re faced with a black screen with the solitary message “MBR Error” with a value of 1, 2 or 3 or the information that “Windows failed to start.” Luckily, it’s only a software issue and not all that hard to fix the MBR in Windows 10.

Why Do MBR Errors Happen?

The reasons for MBR errors could be due to, but not limited to:

  • Corrupted or deleted boot files
  • Removing the Linux operating system from a dual-boot computer
  • Mistakenly installing an older version of boot record, etc.

Access Windows Recovery and Command Prompt

Note: we’re showing how to do this in Windows 10, but the process is largely similar for Windows 7 and 8, too.

If you have a boot record problem, then you probably won’t be able to reach the Windows desktop and open the command prompt from there. In this case you have to insert the Windows OS installation media and boot from that. On the installation screen click “Next,” then “Repair your computer.”

fix-mbr-in-windows-10-repair-your-computer

The above action will open the System Recovery Options window. Here select “Troubleshoot,” then “Command Prompt”.

fix-mbr-in-windows-10-troubleshoot

Since we need the command prompt to work with, select the option “Command Prompt.”

Note: if you are using Windows 8 or 8.1, then press the F8 or Shift + F8 keys on your keyboard while booting, select the option “Troubleshoot -> Advanced Settings” and then again select Command Prompt from the list of the options to open the Command Prompt window.

Fix the MBR

Once you are in the command prompt, we can start fixing the boot record error using the bootrec command. Most of the time boot record problems are a direct result of a damaged or corrupted Master Boot Record. In those scenarios simply use the below command to quickly fix the Master Boot Record.

Once you execute the command, you will receive a confirmation message letting you know, and you can continue to log in to your Windows machine.

fix-mbr-in-windows-10-command-prompt

If you think your boot sector has been either damaged or replaced by the other boot loaders, then use the below command to erase the existing one and create a new boot sector.

Besides corrupted boot records, boot record errors may also occur when the “Boot Configuration Data” has been damaged or corrupted. In those cases you need to use the following command to rebuild the Boot Configuration Data. If the BCD is actually corrupted or damaged, Windows will display the identified Windows installations to rebuild the entire BCD.

If you have installed multiple operating systems on your Windows machine, then you might want to use the “ScanOS” argument. This parameter commands Windows to scan and add all the missing operating systems to the Boot Configuration Data. This enables the user to choose an operating system while booting.

Conclusion

Yes, it’s that simple to fix the MBR in Windows 10. Do comment below if you face any problems while using the above commands to fix the boot record errors or to simply share your thoughts and experiences regarding boot record errors in Windows.

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10 comments

  1. Most Windows 10 users will not possess any Windows OS installations media, as such are no longer provided as standard when purchasing a computer loaded with that OS. Will the procedure outlined above work if one uses a bootable USB drive containing a Windows 10 ISO file which is not specific to the computer on which the failure has occurred ?…

    Henri

    1. I should probably clarify that by ‘installation media’, I’m also referring to the Windows ISO file/bootable USB. That will work.

  2. Most newer machines with windows 7 and later don’t comes with the Windows installation disk. The instructions above are useless.

  3. I agree with the other comments. The install discs are not shipped with your unit, so it makes this article basically worthless. Had my whole system corrupted because of a Windows update that caused the issue with the MBR. It had to be completely reimaged, which really sucked.

  4. Don’t have the Windows 10 install disk? So just download it from Microsoft. Mr. Zak should have mentioned that.

    https://www.microsoft.com/en-us/software-download/windows10

  5. How can anyone have any confidence on this rather pathetic attempt to show a fix that depends on something most people will not have? DUH!!
    They are also highly unlikely to have a bootable USB.
    Why not start again with “creating & use testing a bootable USB drive”.
    Then maybe explain the various steps to repair the MBR.
    BTW in my experience several attempts are sometimes needed, so don’t give up if the repair is not immediately successful.

  6. my pc was initially running good with windows 10 enterprise. it later requested for windows activation which I failed to do due lack of strong WiFi in our rural home as I am currently on long holiday. then it started to pop up some error messenges of application for some days and now it has failed to boot up into windows after I restarted. it give me some repair options then it still fail to fix the error and doesnt boot into windows. PLIZ HELP good Samaritans…thanks for your support.

  7. I tried this on my SSD, /fixmbr reported successful but failed to boot. /scansos found 1 windows installation, but neither /fixboot, nor /rebuildbcd worked both returned “element not found”

  8. Ran:
    bootrec /ScanOs
    Total identified windows installations: 0
    bootrec /RebuildBcd
    Total identified windows installations: 0

    Early on there was the address of an error log. I did not record that address. What is that address and does it contain useful information. It would be nice when code detects a problem that it inform the user as to the nature of the problem and recommended solution. Having an automatic recovery process is nice when it works. When it fails the user is left to guess as to the nature of the original condition which caused the problem. No telling how much damage I have done trying solutions from the Internet!

  9. I have no idea why Windows 10 went into repair mode in the first place. I have two laptops with Windows 10 and have installed Ubuntu 18.04 dual boot. One is still working. The other just decided to go into repair mode one day – reason unknown.

    More information: [my notes in reverse day order]
    *****
    12/06/2018
    Big Problem: Ubuntu has broken Windows.
    **
    Re-installing Windows 10 on RobotSys: NG
    Recovery failed.
    **
    Need to run: bootrec /fixmbr
    From command prompt
    **
    Ran/shutdown system
    **
    Still does not start.
    **
    diskpart:
    list disk
    select disk 0
    list partition
    **
    Partition ### Type Size Offset
    Partition 1 System 260 MB 1024 KB
    Partition 2 Reserved 16 MB 261 MB
    Partition 3 Primary 628 GB 277 MB
    Partition 6 Unknown 206 GB 629 GB
    Partition 4 Primary 95 GB 835 GB
    Partition 5 Recovery 1000 MB 930 GB
    **
    Need to run:
    bootrec /rebuildbcd
    bootrec /fixmbr
    bootrec /fixboot [not authorized]
    chkdsk /r c:
    **
    Need to run:
    diskpart:
    On computer: MININT-2PDB5RP
    list disk
    select disk 0
    list vol
    select vol 1 [C Windows NTFS Partition 628 GB Healthy]
    assign letter=V
    exit
    V:
    md \efi\microsoft\boot\
    cd /d V:\efi\microsoft\boot\
    bootrec /fixboot [step 14]
    Got: access denied
    bcdboot c:\windows /l en-us /s V: /f all
    Got: failure when attempting to copy boot files.
    **
    Reset RobotSys: remove all files.
    **
    Reset failed.
    *****
    12/05/2018
    Not sure why Windows stopped loading.
    ?
    *****
    11/30/2018
    Partition RobotSys laptop hard drive.
    – 97.6 GB Workarea
    **
    Install Ubuntu Bionic Beaver (18.04.1) on RobotSys.
    – 221 GB Ubuntu drive
    **
    Install ROS Melodic Morenia on RobotSys.
    **
    ROS installation is verified.
    Start terminal: roscore
    Start terminal: rosrun turtlesim turtlesim_node
    Observe turtle in a new window on blue screen: OK
    **
    Windows 10 still runs.
    *****

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