When your computer won't boot, it's easy to panic. Thankfully, if your booting problem is related to the Master Boot Record, as in the case of "Windows failed to start" messages, it's not too difficult to fix.

The MBR is a region on your computer's hard drive that holds information about the partitions on the disk. It also contains information about how the computer should load the OS. While MBR is an older scheme that's being phased out in favor of GPT (GUID Partition Table), many computers still use MBR for backwards compatibility.

Here's how to fix your MBR-related booting issues. These are often caused by corrupted files, and can arise when you've dual-booted a copy of Linux on your Windows machine.

How to Fix the Master Boot Record in Windows 10

  1. Since you can't boot into Windows to access recovery tools, you'll need to create Windows 10 install media on a removable drive. Grab a spare flash drive and follow our instructions for creating a Windows 10 disk.
  2. Plug the flash drive into your PC and boot from it. Click Next once you see the Windows Setup box, then select the Repair your computer link in the bottom-left.
  3. You'll see several recovery options. Select Troubleshoot, then Command Prompt.
  4. Now, you'll need to run one of a few commands in order to repair the MBR. You can reboot after each and try to start up as normal. Try the following repair to start:
            bootrec /fixmbr
        
  5. When it completes, you'll see a message letting you know.
  6. If this command doesn't fix your issue, you can try the next command to erase the existing MBR and create a new one:
            bootrec /fixboot
        
  7. Should the above commands not solve the problem, try using the following one to repair the Boot Configuration Data:
            bootrec /rebuildbcd
        
  8. If you've installed multiple OSes on your computer, run this command to force Windows to check for them all again:
            bootrec /scanos
        

Hopefully, one of the above boot repair commands will resolve your MBR issues.