Sorted this exact problem for a customer two days ago. Black screen, error code 0xc0000034, machine completely dead. Twenty-five minutes later it was booting fine. If your PC is throwing a Boot Configuration Data missing error, this guide covers every fix from the quick one-click repair right through to manually rebuilding the BCD from scratch.

TL;DR

A Boot Configuration Data missing error (often 0xc0000034 or 0xc000000f) means Windows cannot find the file that tells it how to start. Boot into Windows Recovery Environment and run Startup Repair first. If that fails, use bootrec commands or manually rebuild the BCD with bcdboot from Command Prompt.

⏰️ 13 min read ✅ 90% success rate 📅 Updated July 2026

Key Takeaways

Boot Configuration Data missing stops Windows loading entirely. It is a software fault, not a hardware failure, in most cases.
Startup Repair fixes it automatically about half the time with zero command-line work.
The bootrec four-command sequence (fixmbr, fixboot, scanos, rebuildbcd) handles the majority of remaining cases.
If bootrec fails, deleting and rebuilding the BCD with bcdboot is the next step.
If chkdsk reports heavy bad sector damage, the drive itself may be failing and needs replacing.

At a Glance

Difficulty: Medium
Time Required: 15 to 30 mins
Success Rate: 90% of cases resolved without hardware work

What Causes Boot Configuration Data Missing?

The BCD (Boot Configuration Data) store is a small database that lives on your system partition. Windows Boot Manager reads it every single time you power on, and it contains the exact instructions for loading your operating system. Think of it as the index at the front of a book. Tear out the index and the book becomes useless, even though every page is still there.

The most common cause we see is an improper shutdown. Power cuts, holding the power button during a Windows update, a laptop battery dying mid-write. Any of these can corrupt the BCD store or the boot sector that points to it. The second most common cause is a failed Windows update that leaves the boot configuration in a half-finished state. Windows 11 updates in particular have caused this on a handful of machines we have worked on this year.

A damaged Master Boot Record (MBR) or EFI boot sector is another culprit. The MBR sits at the very start of the disk and tells the firmware where to find the bootloader. If that gets overwritten or corrupted, the chain breaks before it even reaches the BCD. On UEFI systems it is the EFI System Partition that does the same job. Malware occasionally targets these areas deliberately because corrupting the boot sector is an effective way to make a machine unusable. If you suspect that is what happened here, run a full scan with a bootable antivirus tool after you get Windows back up, and check out our malware removal guide for the full cleanup process.

Less commonly, the system partition simply loses its 'active' flag on BIOS/MBR setups. This can happen after disk management operations or third-party partition tools. Without the active flag, the firmware does not know which partition holds the bootloader, so it never finds the BCD. And finally, physical bad sectors on the drive can corrupt boot files over time. If the drive is making clicking noises or chkdsk keeps finding new errors on repeated runs, that is a sign the hardware itself is failing rather than just the boot configuration.

According to Microsoft's own documentation on BCD system store settings, the BCD store must be present and readable on the correct partition for Windows Boot Manager to function. Any interruption to that chain produces exactly the errors described here.

Boot Configuration Data Missing: Quick Fix

Start here. Startup Repair is automatic, takes about five to ten minutes, and fixes the problem roughly half the time without you typing a single command. No reason to skip straight to the advanced stuff when this might sort it in one go.

Run Startup Repair Easy

Get into Windows Recovery Environment
Power the PC on and off two or three times by holding the power button during the Windows logo. After the second or third failed boot, Windows should automatically show 'Preparing Automatic Repair' and drop you into the recovery screen. If it does not, you need a Windows installation USB. Boot from it, pick your language, click Next, then click Repair your computer at the bottom left. Do not click Install.
Launch Startup Repair
In the recovery menu go to Troubleshoot > Advanced options > Startup Repair. If asked, select your Windows installation from the list. The tool will scan boot files, check the BCD store, and attempt automatic repairs. Let it run completely without interrupting it.
Restart and test
When Startup Repair finishes it will either say it fixed the problem or that it could not. Either way, click Restart and see if Windows loads. If it boots normally, you are done. If the Boot Configuration Data missing error comes back, move to Solution 2.

Windows loads past the boot screen and reaches the login screen or desktop. Job done.

No Windows USB? You can create one on any working PC using the Microsoft Media Creation Tool. Download it, run it, choose 'Create installation media', pick a USB drive of 8 GB or larger, and it handles everything. Takes about 20 minutes depending on your internet speed.

Advanced Boot Configuration Data Missing Fixes

This is where most of the proper repair work happens. The bootrec tool is what Microsoft built specifically for this situation, and in our experience it fixes the Boot Configuration Data missing error in the majority of cases where Startup Repair has already failed. You will need the Windows recovery environment and a bit of patience, but the commands themselves are not complicated.

Run bootrec Commands Medium

Open Command Prompt in WinRE
Boot from your Windows USB, click Repair your computer, then go to Troubleshoot > Advanced options > Command Prompt. A black window opens. This is where the actual repair happens.
Run the four bootrec commands in order
Type each command below and press Enter after each one. Wait for each to finish before typing the next:

bootrec.exe /fixmbr
Rewrites the Master Boot Record without touching the partition table. Safe to run.

bootrec.exe /fixboot
Writes a new boot sector compatible with your version of Windows. If you get 'Access is denied' on this one, see the note below.

bootrec.exe /scanos
Scans all disks for Windows installations. Make a note of what it finds.

bootrec.exe /rebuildbcd
Rebuilds the BCD store using the installations found by /scanos. When it asks 'Add installation to boot list? Yes/No/All', type Y and press Enter.
Exit and restart
Type exit and press Enter, then restart the machine. Test whether Windows boots.

Getting 'Access is denied' on /fixboot? This happens on some UEFI systems. Try running bootsect /nt60 sys /mbr first, then retry /fixboot. If it still fails, skip to Solution 5 (bcdboot) which handles this differently.

bootrec /rebuildbcd reports 'Successfully scanned Windows installations' and Windows boots after restart.

Delete and Rebuild BCD with bcdboot Hard

Open Command Prompt from WinRE
Same as Solution 4. You need Command Prompt from Advanced options.
Remove the damaged BCD file
Run these three commands in order:

attrib -r -s -h c:\boot\bcd
Strips the read-only, system, and hidden attributes so the file can be deleted.

del c:\boot\bcd
Deletes the corrupted BCD store. Do not worry, the next command creates a fresh one.

bcdboot c:\windows
Copies the required boot files from your Windows installation and creates a brand new BCD store. This is the cleanest possible rebuild.
Restart and verify
Type exit, restart the machine, and check whether Windows loads. Took three reboots before this one stuck on a particularly stubborn machine last month, so if the first restart drops back to the error screen, try restarting once more before assuming it failed.

Make sure your Windows partition is actually on C: before running these commands. If you are not sure, type dir c: in Command Prompt. If you see a Windows folder listed, C: is correct. If not, try dir d: or dir e: until you find it, then substitute that letter in the commands above.

bcdboot reports 'Boot files successfully created' and Windows loads normally after restart.

Mark System Partition Active + Run chkdsk Hard

Check and set the active partition (BIOS/MBR systems only)
In Command Prompt from WinRE, type the following commands one at a time:

diskpart
list disk
Note the disk number (usually 0).

select disk 0
list volume
Find the volume that contains your Windows system partition (usually labelled System Reserved or has the Windows drive letter).

select volume X (replace X with the correct volume number)
active
exit

This marks the partition as active so the firmware knows where to look for the bootloader. On UEFI systems this step is not needed, but it does no harm to check.
Run chkdsk to repair file system errors
Still in Command Prompt, run:

chkdsk C: /f /r /b

This checks for file system errors (/f fixes them), bad sectors (/r recovers readable data), and re-evaluates previously flagged bad clusters (/b). It can take 20 to 40 minutes on a large drive. Let it finish completely.
Reattempt bootrec or bcdboot after chkdsk
If chkdsk found and fixed errors, run the bootrec sequence from Solution 4 again, or bcdboot from Solution 5. Disk errors can prevent those tools from writing correctly, so fixing the disk first and then rebuilding the BCD is the right order.

According to HowToGeek's boot repair reference, running chkdsk before attempting BCD repairs on a drive with known errors significantly improves the success rate of bootrec and bcdboot.

chkdsk completes without critical errors, bootrec or bcdboot succeeds, and Windows boots normally.

If you have worked through all six solutions and the Boot Configuration Data missing error is still appearing, the drive itself is likely failing. At that point, stop running repair tools and focus on getting your data off the drive first. Check out our guide to signs of a failing hard drive to assess whether you are dealing with a hardware problem rather than a software one.

Preventing Boot Configuration Data Missing

Once you have fixed it, you do not want to be back here in three months doing it again. Here is what actually makes a difference, in order of importance.

1. Proper shutdowns, always. This is the big one. The majority of BCD corruption cases we see trace back to a forced power-off during an update or a power cut mid-write. Get a UPS if power cuts are common in your area. Never hold the power button to shut down unless the machine is completely frozen and you have no other option.

2. Keep a Windows recovery USB ready. Create one now, while the machine is working, using the Windows recovery USB creation guide. Label it and put it somewhere you will find it. When the BCD breaks you cannot create recovery media on the broken machine, and scrambling to find a working PC at 11pm is not fun.

3. Run chkdsk every few months. Open Command Prompt as administrator and run chkdsk C: /f. It will schedule a check on the next reboot. Catching bad sectors early, before they reach the boot partition, prevents a lot of grief.

4. Do not touch the EFI System Reserved partition. Partition management tools will let you delete or resize it. Do not. That partition holds the boot files and BCD. Deleting it means rebuilding everything from scratch, and on some systems that is a proper pain.

5. Stick to Microsoft tools for boot settings. Third-party boot managers and dual-boot tools occasionally overwrite the BCD or MBR in ways that break Windows Boot Manager. If you need to manage boot entries, use bcdedit from an elevated Command Prompt. It is the right tool for the job.

Boot Configuration Data Missing: Summary

A Boot Configuration Data missing error looks catastrophic but it is almost always fixable without reinstalling Windows from scratch. Start with Startup Repair, which handles minor corruption automatically. If that fails, the bootrec four-command sequence (fixmbr, fixboot, scanos, rebuildbcd) fixes the majority of remaining cases. For badly corrupted BCD stores, deleting the BCD file and running bcdboot gives you a clean rebuild. Mark the system partition active and run chkdsk if the other tools are not sticking. The only time this becomes a hardware problem is when the drive itself is failing, and chkdsk will tell you that clearly enough. Follow the prevention steps above and you are unlikely to see this error again.

Quick Reference

Error codes: 0xc0000034, 0xc000000f
Tool 1: Startup Repair (WinRE, no commands needed)
Tool 2: bootrec /fixmbr /fixboot /scanos /rebuildbcd
Tool 3: attrib + del + bcdboot c:\windows
Tool 4: diskpart active flag + chkdsk C: /f /r /b
If all fail: drive may be physically failing, prioritise data recovery

Boot Configuration Data missing