Bcd Boot Repair | Fix Startup Errors In Minutes

A bcd boot repair restores the boot configuration data so Windows can start again after errors like Bootmgr missing or 0xc000.

A broken boot record feels dramatic because the PC looks fine, yet it refuses to load Windows. Most of the time the files on your Windows drive are still there. The part that’s confused is the tiny set of boot files and entries that tell the firmware where Windows lives and how to launch it.

If you’ve never done a bcd boot repair before, don’t worry. You’re not editing your personal files here; you’re rebuilding the boot map that points to them.

This guide walks through a clean, low-drama way to repair those boot entries on Windows 10 and Windows 11. You’ll start with the built-in repair option, then move to a few command-line steps that rebuild the BCD store the right way for your system type.

Bcd Boot Repair Basics For Windows Startup

BCD stands for Boot Configuration Data. Think of it as the index card Windows reads at startup. It lists the installed Windows entry, the loader path, and a few settings that control how the boot manager behaves.

When that store is missing or corrupted, you can see messages like “Bootmgr is missing,” “0xc000000f,” “The boot configuration data file is missing,” or a loop where the machine keeps dropping into repair screens.

Two boot styles matter because the fix steps differ.

UEFI With GPT — Most modern PCs. Boot files live on a small FAT32 EFI System Partition.
Legacy BIOS With MBR — Older systems. Boot code lives in the master boot record and the active system partition.

Error You See	What It Usually Means	What To Try First
Bootmgr is missing	Boot files or boot entry can’t be read	Startup Repair, then rebuild BCD
0xc000000f	BCD entry points to the wrong place	Rebuild BCD, then run bcdboot
No boot device found	Firmware can’t find a valid loader	Check boot order, then recreate EFI files
bootrec /fixboot access is denied	UEFI systems can block that write	Skip /fixboot and use bcdboot on EFI

Before You Change Anything

Boot fixes are usually safe, yet you’re still writing to system partitions. Take two minutes to avoid the classic “repair worked, but now I can’t unlock the drive” situation.

Check For BitLocker — If your Windows drive is encrypted, have your recovery password ready before you start.
Unplug Extra Drives — Leave only the Windows drive connected, plus the USB installer if you’re using one. This keeps boot files from being written to the wrong disk.
Know Your Windows Letter — In Windows RE, the Windows partition is often not C:. You will verify the letter before running commands.
Use A Matching Installer — If you boot from a Windows 11 USB to fix Windows 11, your tools and files line up cleanly.

If you can still reach the Windows sign-in screen, pause and copy your must-have files to an external drive first. If you can’t boot at all, the steps below still work, just move carefully.

Boot Repair After BCD Damage On Windows

Make A Quick BCD Backup If You Can See The Windows Drive

If the Windows partition is readable in the recovery console, you can export the current BCD store before you rebuild anything. If the store is badly damaged, the export may fail. If it succeeds, you get a simple rollback file.

bcdedit /export W:\BCD_Backup

Use the Windows partition letter you confirmed earlier. You can later import that file back into the BCD store if you need to undo a change.

Start with the built-in repair option. It fixes a lot of boot issues without you touching partitions. If it doesn’t stick, you’ll move to a controlled set of commands.

Get Into Windows RE

You can reach Windows RE in a few ways. Pick the one you can do right now.

Use The Power-Cycle Method — Turn the PC on, then hold the power button to shut it off as soon as Windows begins to load. Repeat two times. On the third start, the recovery menu often appears.
Boot From A Windows USB — Start from the installer, then choose the repair option instead of installing Windows.
Use A Built-In Recovery Shortcut — On many PCs you can press F11 or a vendor shortcut at boot to open recovery tools.

Run Startup Repair First

In the recovery menu, choose the automated startup repair option and let it finish. If it boots normally afterward, stop there. If it still fails, come back and open Command Prompt.

Rebuild The BCD Store With Bootrec

These commands are most useful on BIOS/MBR systems, and they can still help on some UEFI systems when the BCD store is damaged. Type them one at a time and press Enter after each line.

bootrec /scanos
bootrec /rebuildbcd

If the tool finds your Windows install and asks to add it to the boot list, choose Yes.

If you’re on an older MBR setup and you suspect the boot code itself is broken, you can also run the classic pair below before rebuilding the BCD store.

bootrec /fixmbr
bootrec /fixboot

If bootrec /fixboot throws “Access is denied,” don’t fight it. That message is common on UEFI systems. Skip to the UEFI section where you rebuild the EFI files with bcdboot instead.

Bcd Boot Repair For UEFI GPT Systems

On most Windows 10 and Windows 11 machines, UEFI and GPT are in play. In that setup, the cleanest fix is to assign a drive letter to the EFI System Partition, then copy fresh boot files using bcdboot.

Microsoft documents the bcdboot options and the way it recreates system partition files when they’re damaged. You can read the reference on Microsoft Learn if you want the full switch list.

BCDBoot command options on Microsoft Learn

Find The EFI Partition And Give It A Letter

In Command Prompt, open DiskPart and list volumes. You’re looking for a small FAT32 volume, often 100–300 MB, with no drive letter.

diskpart
list vol

Pick the EFI volume number, then assign a letter you’re not using, like S.

select vol 1
assign letter=S
exit

Confirm Your Windows Partition Letter

Still in Command Prompt, check which letter contains the Windows folder. Try C: first, then D:, then E: until you see the Windows directory.

dir C:\Windows
dir D:\Windows

Copy Fresh Boot Files With Bcdboot

Once you know the Windows letter, run bcdboot to rebuild the boot files on the EFI partition. Replace W: with your Windows partition letter if it isn’t C:.

bcdboot W:\Windows /s S: /f UEFI

If you’re unsure which firmware mode the machine will use, you can swap /f UEFI for /f ALL to write both sets of boot files. If the boot menu text shows the wrong language, add /l en-us (or your locale) to the same command and rerun it.

Restart and test. If the PC now boots, you’re done.

Fix The “Access Is Denied” Fixboot Error

If you got blocked by bootrec /fixboot, this is the clean workaround for most UEFI cases. You rebuild the EFI boot files with bcdboot as shown above, then reboot.

If you still need a boot sector write on a BIOS/MBR machine, one option is to run Bootsect to rewrite the boot code, then rebuild the BCD store again.

bootsect /nt60 sys
bootrec /rebuildbcd

Fixes When Rebuild BCD Finds Zero Installs

Sometimes bootrec /scanos returns 0 Windows installations. That usually means Windows is on a partition that is not mounted the way the tool expects, or the file system has errors.

Check The Disk And Partition Letters

List Volumes Again — Run DiskPart and confirm which volume is your Windows partition and which is EFI.
Try Dir On Likely Letters — Use dir to confirm where \Windows lives before you run any copy commands.
Keep Only One OS Drive — Disconnect other internal drives, then rerun the scan.

Repair The File System Offline

If the Windows partition letter is W:, run a disk check. This can take a while on large drives.

chkdsk W: /f

Repair Windows Files Offline

When the boot issue started after a crash or a forced shutdown, system files can be damaged. You can check and repair them from the recovery console.

sfc /scannow /offbootdir=W:\ /offwindir=W:\Windows

If SFC can’t fix everything, try DISM with a local install source. If your USB installer is D:, and your Windows partition is W:, this pattern is common.

dism /image:W:\ /cleanup-image /restorehealth /source:D:\sources\install.wim

Keep Boot Files Stable After The Repair

Two Small Checks That Save Time

Confirm Boot Order — In firmware setup, make sure Windows Boot Manager is above USB and network entries once you’re done testing.
Check Date And Time — A wildly wrong clock can trip Secure Boot checks on some systems. Set it correctly before you retry boot.

A boot repair is only half the story. If the BCD broke because of disk errors, a rushed update, or a dual-boot tweak, the same failure can come back. These habits cut the odds.

Run A Drive Health Check — Use the drive maker’s tool or a SMART reader inside Windows once you can boot. If the drive is failing, no boot fix lasts long.
Finish Updates Fully — Let major Windows updates complete their reboots before you power off.
Avoid Random Partition Tools — Shrinking, moving, or cloning partitions can confuse boot entries. If you must clone, verify boot order and test a restart right after.
Keep A Recovery USB — A bootable installer USB saves time when the PC won’t reach the desktop.
Back Up Your Files — Use File History, OneDrive, or another backup method so boot problems are annoying, not catastrophic.

Command Recap You Can Screenshot

Scan For Installs — bootrec /scanos
Rebuild BCD — bootrec /rebuildbcd
Assign EFI Letter — diskpart then list vol, select vol #, assign letter=S
Recreate EFI Files — bcdboot W:\Windows /s S: /f UEFI
Offline File Check — sfc /scannow /offbootdir=W:\ /offwindir=W:\Windows

If you ever see the same boot error twice in a week, treat that as a signal. Check disk health and cabling, then revisit the boot steps above. That pattern often points to storage trouble, not a one-off BCD glitch.

Once you’ve done the steps here, you’ve completed a bcd boot repair that matches your firmware style and restores the boot files Windows needs to start. If the machine still won’t boot after a clean EFI rebuild and offline file checks, the next move is hardware testing or a Windows reset from the recovery menus.