Error codes

0xc0000034

The boot configuration data file is missing required information

What it means

The BCD entry Windows points at is incomplete, so the boot manager cannot tell which device or partition to load.

Common causes

• A half-written BCD after a failed update
• A drive or partition that changed its ID
• A dual-boot tool that edited the entry

How to fix it

1. Start the PC from the Windows install stick or recovery drive, then choose Repair your computer > Troubleshoot > Advanced options > Command Prompt.
2. Run bootrec /rebuildbcd and answer yes to adding the Windows installation it finds.
3. If it still fails, run bcdboot C:\Windows /s S: /f UEFI with S: replaced by your EFI partition letter.