Fix Boot Configuration Data Error 0xc0000185

Boot configuration data error 0xc0000185 appears when Windows 10 cannot read the Boot Configuration Data (BCD) store during startup, often caused by disk errors, corrupted BCD files, or failing hardware. You can usually fix it by running the Startup Repair tool, rebuilding the BCD from the command prompt, or checking your hard drive with CHKDSK. Below are the exact steps, what causes the error, and what to do if the standard fixes don’t work.

What Is Boot Configuration Data and Why Does It Fail?

The Boot Configuration Data (BCD) store is a small database that Windows uses to load the operating system. It contains boot options, such as which partition to boot from, the path to the Windows loader, and recovery options. When the BCD is missing, corrupted, or unreadable, Windows displays error 0xc0000185 with a message like “The boot configuration data for your PC is missing or contains errors.”

Common causes include:

Sudden power loss during a shutdown or while Windows is writing to the BCD.
Disk errors on the system partition (bad sectors, file system corruption).
A failed Windows update that interrupted the boot files.
Third-party disk tools or dual-boot setups that modified the BCD incorrectly.
Hardware issues, such as a failing hard drive or a faulty SATA cable.

Note that error 0xc0000185 is different from 0xc0000189 or 0xc000000f, which also relate to BCD problems but may have slightly different causes. The fix steps are largely the same, but if you see a different code, check the exact message for clues.

How to Access Windows Recovery Environment

Most fixes require booting into the Windows Recovery Environment (WinRE). If Windows won’t start normally, you can still reach it:

Turn on your PC and wait for the Windows logo. When it appears, press and hold the power button to force shutdown.
Repeat this two or three times. On the next boot, Windows should display “Preparing Automatic Repair” and then load the recovery screen.
Alternatively, if you have a Windows 10 installation USB, boot from it and click “Repair your computer” on the setup screen.
Once in the recovery environment, go to Troubleshoot > Advanced options.

From here, you can access the tools described below. If you don’t have a recovery partition or USB, you may need to create one on another working PC.

Fix 1: Run Startup Repair

Startup Repair is the simplest fix and often resolves BCD errors automatically. It scans the system for problems and attempts to repair boot files without affecting your personal data.

From the Advanced options screen, select Startup Repair.
Choose your user account and enter your password if prompted.
Windows will diagnose and attempt to fix the issue. This may take several minutes.
If it succeeds, restart your PC. If it fails, proceed to the next fix.

Startup Repair works best when the BCD is slightly corrupted but the disk is otherwise healthy. If the error persists, you’ll need to rebuild the BCD manually.

Fix 2: Rebuild the BCD from Command Prompt

If Startup Repair doesn’t help, you can manually rebuild the BCD using the bootrec tool. This is the most common fix for 0xc0000185.

From Advanced options, select Command Prompt.
Type the following commands one by one, pressing Enter after each:

bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd

/fixmbr repairs the master boot record (MBR) on the system partition.
/fixboot writes a new boot sector.
/scanos scans for Windows installations.
/rebuildbcd rebuilds the BCD store from scratch.

If you get an “Access is denied” error when running /fixboot, you may need to run the command on the correct volume. Type diskpart, then list volume to see your partitions. Identify the system partition (usually the one with a size of 100MB or 500MB, labeled “System”). Then run sel vol X (replace X with the volume number) and assign letter=S. Exit diskpart and run bcdboot C:\Windows /s S: (adjust the Windows drive letter if needed). This copies new boot files to the system partition.

Fix 3: Check and Repair Disk Errors

Disk corruption can cause the BCD to become unreadable. Running CHKDSK can fix file system errors and bad sectors.

Open Command Prompt from Advanced options as above.
Type chkdsk C: /f /r and press Enter. Replace C: with the drive letter where Windows is installed (often C:, but check with diskpart if unsure).
If the drive is in use, you may be prompted to schedule a check. Type Y and restart.

CHKDSK can take a long time, especially on large drives. It will attempt to recover readable information from bad sectors and fix file system errors. If it reports severe damage, consider backing up your data immediately, as the drive may be failing.

Fix 4: Check Hardware and BIOS/UEFI Settings

If the software fixes don’t work, the problem could be hardware-related. A failing hard drive, a loose SATA cable, or incorrect BIOS/UEFI settings can cause this error.

Check connections: Power off your PC, open the case, and reseat the SATA data and power cables on the hard drive. If you have an SSD, try a different SATA port.
Run hardware diagnostics: Many PC manufacturers include a built-in diagnostic tool (accessible via F12 or a similar key at boot). Run the hard drive test. If it fails, replace the drive.
Check BIOS/UEFI boot mode: If Windows was installed in UEFI mode, ensure the BIOS is set to UEFI (not Legacy/CSM). If it was installed in Legacy mode, set it to Legacy. Mismatched settings can cause BCD errors.
Disable fast boot: Some systems have a “Fast Boot” option in BIOS that can cause boot issues. Try disabling it temporarily.

If you recently changed BIOS settings, revert them to defaults. Also, if you have multiple drives, try disconnecting all but the Windows drive to see if the system boots.

What to Do If Nothing Works

If you’ve tried all the above and the error persists, you may need to reset Windows or reinstall it. Before doing that, try to back up your data:

Boot from a Windows installation USB and select “Repair your computer” > “Troubleshoot” > “Command Prompt”. Copy your personal files to an external drive using copy or robocopy commands. If you’re not comfortable with the command line, you can use a live Linux USB to copy files.
If you can access the recovery environment, you can also try “System Restore” to roll back to a previous restore point. This may fix the BCD if the issue started recently.

If you choose to reset Windows, you can keep your personal files, but you’ll lose installed apps. A full reinstall will erase everything, so back up first.

Frequently Asked Questions

Can I fix error 0xc0000185 without a Windows installation USB?

Yes, if you can access the Windows Recovery Environment through the automatic repair loop. If that doesn’t work, you’ll need a USB or DVD with Windows 10 installation media. You can create one on another PC using Microsoft’s Media Creation Tool.

Will rebuilding the BCD delete my files?

No. Rebuilding the BCD only recreates boot configuration files. It does not touch your personal files, documents, or installed programs. However, it’s always wise to back up important data before any repair, just in case.

What is the difference between MBR and GPT, and does it matter?

MBR (Master Boot Record) and GPT (GUID Partition Table) are two partitioning schemes. Windows 10 can boot from both, but the BCD location and the boot mode (Legacy vs UEFI) differ. If you’re not sure which one you have, check your BIOS settings. If you see “UEFI” and “Legacy” options, try both if the error persists.

Why do I get “Access is denied” when running bootrec /fixboot?

This usually happens when the system partition is not visible or has no drive letter. Use diskpart to assign a letter to the system partition, as described in Fix 2, then run bcdboot to copy boot files. This gives the command access to the correct volume.

Can a failing hard drive cause 0xc0000185?

Yes. If the hard drive has bad sectors in the area where the BCD is stored, Windows may not be able to read it. CHKDSK can sometimes recover data, but if the drive is physically failing, you may need to replace it. Run the manufacturer’s diagnostic tool to test the drive.

Is it safe to run chkdsk /f /r on my system drive?

Yes, it’s safe, but it may take a long time. It will attempt to fix file system errors and mark bad sectors. It’s best to back up important data first, as CHKDSK can sometimes cause data loss on severely corrupted drives. If you’re worried, have a professional look at it.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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