Fix Error 0xc0000034: Boot Configuration Data File Is Missing

The fast answer. Error 0xc0000034 ("The Boot Configuration Data file is missing some required information", usually showing File: \Boot\BCD or \EFI\Microsoft\Boot\BCD) means Windows Boot Manager found no usable boot entry — the BCD store is missing, damaged, or lacks a required entry. Boot into Windows Recovery (WinRE), run Startup Repair, and if that fails rebuild the BCD from Troubleshoot → Advanced options → Command Prompt:

bootrec /scanos
bootrec /rebuildbcd

Type Y to add the Windows installation it finds, then reboot. On a UEFI/GPT machine, recreate the boot files with bcdboot instead (Step 5).

Why this happens

Missing or damaged BCD entries — the boot store exists but no longer holds a valid Boot Manager or Windows entry, or the file itself is gone. This is the most common cause.
An interrupted or failed update — power loss or a forced shutdown while Windows was updating boot files leaves the store incomplete.
Partition, clone, or dual-boot changes — resizing partitions, cloning to a new drive, or removing a second OS can leave BCD entries pointing at nothing.
File-system damage or bad sectors — corruption on the system partition that holds the BCD, sometimes from a failing drive.

Step-by-step fix

Step 1 — Get into Windows Recovery (WinRE)

Force three failed boots (power on, then hold the power button as the Windows logo appears, three times) to open Automatic Repair, or boot from a Windows 10/11 install USB and choose Repair your computer. If the on-disk recovery environment won't load, the install USB is the reliable route. Then go to Troubleshoot → Advanced options.

Step 2 — Run Startup Repair

Choose Startup Repair and let it finish. It repairs many missing or damaged BCD entries automatically. Reboot and test before running any commands.

Step 3 — If it started after an update, uninstall the update

If the error appeared right after Windows Update, go back to Advanced options → Uninstall Updates and remove the latest quality update. This doesn't touch your files. Reboot and test.

Step 4 — Rebuild the BCD with bootrec

In Advanced options → Command Prompt, run:

bootrec /scanos
bootrec /rebuildbcd

When /rebuildbcd lists a Windows installation, type Y to add it and reboot. If it reports "Total identified Windows installations: 0" on a legacy BIOS system, back up and rename the old store, then rebuild:

bcdedit /export C:\bcdbackup
attrib C:\boot\bcd -h -r -s
ren C:\boot\bcd bcd.old
bootrec /rebuildbcd

Use the letter of the volume that holds the \Boot folder — in WinRE, drive letters often differ from normal Windows. Check with dir C:\boot first.

Step 5 — UEFI/GPT: recreate the boot files with bcdboot

On UEFI machines the BCD lives on the small FAT32 EFI System Partition. Assign it a letter and let bcdboot rebuild the store from the Windows folder:

diskpart
list disk
sel disk 0
list vol
sel vol <EFI-FAT32-vol#>
assign letter=S:
exit
bcdboot C:\Windows /s S: /f UEFI

The EFI partition is the ~100–500 MB FAT32 volume. Replace C:\Windows if Windows has a different letter in WinRE (confirm with dir C:\Windows). You should see "Boot files successfully created." Don't rely on bootrec /fixboot here — on UEFI it commonly returns "Access is denied"; see the full bcdboot walkthrough.

Step 6 — Check the disk

If the error returns, check the Windows volume for file-system damage (use the correct letter):

chkdsk C: /f /r

If chkdsk finds bad sectors, or the BCD breaks again soon after a rebuild, treat the drive as failing: back up and plan a replacement instead of repeating repairs.

Data safety: bootrec, bcdboot, and renaming the BCD change only boot data, not your documents. The risky parts are chkdsk /r, which stresses weak sectors on a failing drive, and diskpart, where one wrong volume number can destroy a partition. If the files matter and you have no backup, image the drive to a known-good external disk first, never run clean or format in diskpart for this error, and never run repairs on the only copy of irreplaceable data.

GRAM tip: These repairs run in Windows Recovery, which is already on the broken PC or any Windows install USB. Once the machine boots again, plug in GRAM — a free portable repair toolkit that runs from a USB inside Windows — to check the drive's SMART health, read the event logs for failed updates and unexpected shutdowns, and let its AI agent confirm why the boot data went missing so the error doesn't come back.

Download GRAM free See AI pricing →

FAQ

Can I fix this without a second working computer?

Usually, yes. WinRE lives on the broken PC itself — three failed boots trigger Automatic Repair, where Startup Repair and Command Prompt are available. If the boot data is too damaged for WinRE to load, boot a Windows install USB (made on any PC, even a borrowed one) and choose Repair your computer. The repair itself needs no second computer. (GRAM runs inside Windows rather than from boot media — use it once the machine boots to verify disk health and confirm the root cause.)

Will rebuilding the BCD delete my files?

No. The BCD is a small boot database; bootrec /rebuildbcd and bcdboot rewrite boot configuration only. Documents and programs are untouched. Custom boot entries, such as a second OS, may need to be re-added afterward.

What's the difference between 0xc0000034 and 0xc000014c?

Both are BCD errors and share the same repair path. 0xc0000034 typically means the store or a required entry in it can't be found; 0xc000014c typically means the store is present but corrupt or unreadable. Start with Startup Repair either way, then rebuild with bootrec or bcdboot.

Startup Repair and bootrec both failed. What now?

On UEFI machines, use bcdboot (Step 5) — it's often the fix when bootrec isn't. Also check BIOS: the boot mode (UEFI vs Legacy/CSM) must match how the disk was set up. If nothing works, run chkdsk, back up your data, and consider reinstalling Windows.