Here’s how to fix corrupt MBR issues (Boot sector)

Aleksandar Ognjanovic
by Aleksandar Ognjanovic
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fix corrupt mbr fix corrupt boot sector

Corrupted MBR or boot sector means a lot of trouble. You’ll have a hard time booting into Windows until you deal with it. If you’ve tried to boot into Windows and the boot sector error appeared on a dark screen, this almost always points towards corrupt MBR or critical HDD failure.

We have a few ways to resolve this, so make sure to check the steps we enlisted below.

Steps to fix corrupt boot sector  problems (MBR)

  1. Rebuild MBR
  2. Scan for HDD errors
  3. Perform a clean reinstallation

1: Rebuild MBR

This isn’t one of those common errors you’ll deal on regular basis. Issues with the boot sector mostly occur due to an HDD corruption or misuse of certain system files. Which makes it a large-scale critical issue. The black screen and boot failure are pretty intimidating for an inexperienced user. However, this can be resolved with some effort.

The difficulty of this problem requires certain preparations made on another PC. You’ll need to download the Media Creation Tool and create a bootable installation drive. You can use DVD and burn the setup files, but we prefer using a USB flash drive with storage space of at least 6 GB. After you’ve done that, the whole complex process awaits.

Here’s how to rebuild MBR and fix the boot sector error:

  1. Insert the Windows 10 bootable media (USB stick or DVD) and restart your PC.
  2. Set the bootable media with the Windows 10 installation as the primary boot device. Change the boot order by either entering the Boot menu or within BIOS settings.
  3. Press any key to boot.
  4. The loading process of the installation file should commence.
  5. Select the preferred language, time/format, and keyboard input. Hit the ”Next” button.
  6. In the following dialog box, select ”Repair your computer” from the bottom left corner.
  7. Open Troubleshoot from the selection menu.
  8. Choose Advanced Options.
  9. Open Command Prompt. If prompted, select your account and enter the password.
  10. In the command line, type the following commands and press Enter after each:
    • bootrec /FixMbr
    • bootrec /FixBoot
    • bootrec /ScanOs
    • bootrec /RebuildBcd
  11. Exit, remove the installation drive and try starting the system in a normal manner.

2: Scan for HDD errors

A boot sector failure and MBR corruption won’t occur without any reason. This mostly happens in scenarios when your HDD is on its deathbed and you should seriously consider replacing it. This is, on many occasions, a clear sign that you should backup your data as soon as possible, as the HDD either has corrupted sectors or it’s malfunctioning. On the other hand, this isn’t a rule of thumb.

Before you ditch your storage, make sure to inspect it. Some errors can be repaired with the proper tools, either third-party tools or a built-in ChkDsk. If you’re still unable to boot, you can run ChkDsk from the command line in a System Repair section. This is a rather simple task, but it still requires a bootable media in order to run it.

Here’s how to scan HDD for errors if the PC won’t boot into the system:

  1. Boot with the USB installation media and press Shift + F10 to open the Command Prompt.
  2. In the command line, type chkdsk /f /r and press Enter.
  3. After the HDD issues are resolved, restart your PC and try booting into Windows again.

3: Perform a clean reinstallation

In the end, if you’re certain that your HDD is in good health but you’re still unable to boot into Windows, we can only suggest a clean reinstallation. This, of course, means you’ll lose all data from the system partition. So, if there’s any way for you to connect your HDD to another PC and back up the data — do it. After that, we can boot with the installation media and install a clean version of Windows. That way, the problem should be resolved.

Here’s how to perform  a clean reinstallation of Windows 10:

  1. Download the Media Creation Tool from here.
  2. Plug in the USB flash drive with at least 6 GB.
  3. Run Media Creation Tool and accept the License Terms.
  4. Choose ”Create installation media (USB flash drive, DVD, or ISO file) for another PC”.
  5. Choose the fitting language, architecture, and edition and click Next.
  6. Select USB flash drive and then click Next.
  7. Media Creation Tool will download the setup and copy the installation files onto the USB flash drive.
  8. Plug in the USB drive into a troubled PC and boot from it.
  9. Enter all required information and choose Install Windows only.
  10. Format system partition and install Windows 10 there.

With that said, we can conclude this article. In case you have additional questions or possibly an alternative way to fix corrupt MBR, feel free to tell us in the comments section below.


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