How to Rebuild BCD File and Master Boot Record (MBR) in Windows 10?

The Boot Manager in the trendy Windows variations makes use of the BCD (Boot Configuration Data) file to boot the working system put in on the pc. This file comprises details about the put in OS and boot parameters. Windows can not boot usually if the BCD file is deleted or corrupted. Also, you gained’t have the option to boot your Windows if the Mater Boot Record (MBR) on the laborious disk is broken. In this text, we’ll present how to manually rebuild the bwwoot configuration (BCD) file and repair MBR on Windows 10.

If the BCD file is lacking or corrupted, if you happen to eliminated/formatted a separate disk partition with the System Reserved label (and 500 MB in measurement) or a particular , a person is probably going to see the next message when making an attempt to boot Windows 10:

Your PC wants to be repaired
The Boot Configuration Data file is lacking some required info
File: BootBCD
Error code: 0xc0000034

Also, the error might appear to be this::

The Boot Configuration Data on your PC is lacking or comprise errors.

File: bootbcd

Error Code: 0xc000000f

If the MBR is corrupted, there could also be a “No working system discovered” error.

How to Automatically Repair Bootloader in Windows 10?

If this error seems, to begin with strive to repair the issue with booting the OS utilizing the Startup Repair mode that may be began from the Windows Recovery Environment (Windows RE).

Tip. It is advisable to periodically test the health of the WinRE atmosphere, and if it doesn’t work, use the tactic described in the article “” to restore it.

If the automated restore utilizing Startup Repair didn’t assist, boot your laptop from Windows boot/set up disk or in the WinRE atmosphere (Repair your laptop -> Troubleshoot  -> Advanced choices -> Command Prompt). Start the command immediate and strive to create a brand new BCD file and replace the MBR report from scratch.

In this instance, I’ll use Windows 10 set up disk. Change the first boot machine to DVD drive or USB flash drive in the BIOS settings (relying on which machine you need to boot the pc from). Boot your laptop from the Windows set up picture and press Shift + F10 on the language choice display screen. You will see a command immediate.

Try to restore the BCD file robotically utilizing this command:

bootrec /RebuildBCD

Reboot your laptop and test if Windows boots (don’t forget to change the boot precedence settings in BIOS). If it isn’t, boot from the set up disk once more and begin the command immediate.

Identifying Disk Partition Style and Drive Letters

Very essential. All directions given under are appropriate for normal BIOS computer systems with the MBR partition desk. For UEFI-based computer systems you want to use the next guides to or in .

How to perceive when you’ve got a pc with BIOS or UEFI? The simplest way is to test the disk partition desk on which Windows is put in: GPT or MBR. To do that, run the command:


Then checklist accessible disks:

checklist disk

If the disk has an asterisk (*) in the Gpt column, then the GPT partition desk is used on this disk (which means that you might have a pc with UEFI and you want to use the article from the hyperlink above to restore the Windows bootloader). If there is no such thing as a asterisk in the GPT column, then you might have the MBR partition desk on the disk, and you’ll be able to proceed to observe this instruction.


Next, you want have to determine the native drives and volumes in your laptop (it’s possible that the quantity letters assigned to them shall be completely different from these you see when working in Windows). It is simpler to do it utilizing diskpart. Run these instructions:

checklist vol

You will see the checklist of partitions, the drive letters assigned to them and their sizes. In our case, there are one laborious drive on the pc with the 2 volumes on them:

  • System Reserved partition with the dimensions of 500 MB and the drive letter C: assigned to it. By default, BCD file is situated in this little service partition ();
  • NTFS partition with the dimensions of 39 GB and the letter D: assigned. This partition comprises put in Windows, packages and person knowledge.

Important. Remember the assigned drive letters, since they are going to be used in the instructions later.

Repair Master Boot Record (MBR) in Windows 10

Using the next instructions, we’ll overwrite the Master Boot Record on boot sector of your laborious drive, and add the required hyperlinks to Windows 10 bootloader.

bootrec.exe /fixmbr
bootsect.exe /nt60 all /pressure

If bootsect.exe command will not be discovered, strive to specify the total path to it:
X:bootbootsect.exe /nt60 all /pressure

Before shifting on, strive robotically re-creating the BCD bootloader configuration with following instructions (that is the simplest approach for novices):

bootrec /RepairBoot – the command recreates the boot sector on the system partition;
bootrec /ScanOs
bootrec /RebuildBcd – scan all disks and seek for put in Windows, add discovered copies to the BCD bootloader configuration.

After that, restart the pc and test the Windows boot. If the OS doesn’t boot, observe the directions under.

How to Manually Rebuild Boot Configuration File on Windows 10?

Then utilizing BCDedit command, create a brand new Boot Configuration Data file (it’s supposed, you don’t have the ).

Delete the outdated (corrupted) BCD file in System Reserved partition and create a brand new one as a substitute:

del c:bootbcd

If the to the System Reserved partition (by default), you’ll be able to assign it your self utilizing diskpart. Run: diskpart

Select your native disk (in my case, just one laborious disk is put in on the pc, however you’ll be able to checklist native disks with the checklist disk command): choose disk zero

The screenshot above exhibits that the System Reserved partition known as Volume 1. Select it: choose quantity 1

Assign a drive letter (I assigned a letter C: however you should use some other letter, in this case change the trail in the next instructions): assign letter C:


Create an empty momentary file bcd.tmp:

bcdedit /createstore c:bootbcd.tmp

Create an entry for the Boot Manager (bootmgr):

bcdedit.exe /retailer c:bootbcd.tmp /create /d "Windows Boot Manager"

Import settings from bcd.tmp to your BCD:
bcdedit.exe /import c:bootbcd.tmp

Specify that the Boot Manager is situated on the System Reserved partition (the letter C: is assigned to it): bcdedit.exe /set machine partition=c:

Configure the timeout to choose an OS:
bcdedit.exe /timeout 10

Delete the momentary file:
del c:bootbcd.tmp

So now we have a file with the bootloader parameters. Now you might have to add the entries in regards to the put in Windows.

Create a brand new entry for Windows 10 in the BCD configuration:

bcdedit.exe /create /d "Windows 10" /software osloader

The command will return the distinctive identificator (GUID) of this bootloader entry.
The entry was efficiently created.

Specify that bootmgr should use this entry by default (after the timeout, this entry is used to boot):

bcdedit /default

Now you might have to specify the paths to the put in Windows 10 copy in the brand new bootloader entry. We have seen in WinPE that the letter D: is assigned to Windows partition. Use this drive letter in the next instructions.

bcdedit.exe /set machine partition=d:
bcdedit.exe /set osdevice partition=d:
bcdedit.exe /set path Windowssystem32winload.exe
bcdedit.exe /set systemroot Windows

Make this boot report in BCD seen, since it’s hidden by default:
bcdedit.exe /displayorder /addlast

So now we have re-created Windows 10 bootloader and BCD file, and fastened the boot sector on MBR. Now you’ll be able to restart your laptop and be sure that Windows 10 boots as traditional.

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