Fix Windows Error 0xc0000034 - BCD Missing Repair Guide

Your PC is stuck on a blue screen stating the boot configuration data file is missing required information with error 0xc0000034. This typically happens when the Windows boot sector or BCD file becomes corrupted during an update or unexpected power loss. You can fix this by using the Command Prompt from a Windows installation USB to manually rebuild your boot records.

Why this happens

The BCD (Boot Configuration Data) file stores instructions for starting Windows. When it gets corrupted or goes missing, your PC cannot locate the boot files needed to launch the OS.

What you'll need

You need a working computer and a USB flash drive with at least 8GB of space. You will use the Microsoft Media Creation Tool to turn that USB into a bootable Windows installer.

Steps

1. 01
   Plug your bootable USB into the broken PC, power it on, and repeatedly press the BIOS key (usually F2, F12, or Delete) to open the boot menu.
2. 02
   Set the USB drive as the primary boot device, save with F10, and wait for the Windows setup screen to load.
3. 03
   Select your language, click Next, and then click 'Repair your computer' in the bottom-left corner.
4. 04
   Navigate to Troubleshoot > Advanced options > Command Prompt.
5. 05
   Type diskpart and press Enter, then type list volume to identify the drive letter of your Windows installation (look for the largest NTFS volume). Type exit to return to the prompt.
6. 06
   Run bootrec /scanos, bootrec /fixmbr, and bootrec /fixboot one by one. If 'access is denied' appears during the fixboot step, type bootsect /nt60 sys and try bootrec /rebuildbcd again.
7. 07
   When prompted by bootrec /rebuildbcd, type Y to add the installation to the boot list. If you see multiple entries, type Y only for the one pointing to the standard /Windows folder and N for any older versions.
8. 08
   If you receive a 'requested system device cannot be found' error, return to diskpart, use select volume for the small FAT32 partition (100-500MB), type assign letter=B, and then run bcdboot C:/windows /s B: /f UEFI (replace C with your identified drive letter).
9. 09
   Type exit, close the window, and select 'Continue' to restart your PC while removing the USB drive.

Still not working?

If the repair fails, boot back into the Command Prompt and run sfc /scannow followed by chkdsk C: /r (replacing C with your drive letter) to check for file system integrity. If zero Windows installations are found during the rebuild process, your drive's partition table may be incompatible with your BIOS mode, requiring a conversion from MBR to GPT.

Frequently asked questions

Will this fix erase my personal files?

No, these commands only repair the system files responsible for booting Windows. Your personal documents and data remain untouched on the drive.

What if my PC does not see any Windows installations?

This often means the partition table is corrupted or mismatched. You may need to verify if your BIOS is set to UEFI or Legacy mode to match how your drive was originally formatted.