Boot Configuration Data Is Missing: How to Fix It

The “Boot Configuration Data is missing” error means Windows cannot find or read the files that tell it how to start. First check for removable drives and firmware boot settings; if those are correct, use Windows Recovery Environment to repair startup files, taking care to choose the correct Windows installation and disk.

What the error means

Boot Configuration Data (BCD) is a set of boot settings used by Windows Boot Manager. It identifies Windows installations and provides information needed to start them. If the BCD store is missing, damaged, or inaccessible, the computer may stop before Windows loads and show a message such as “The Boot Configuration Data file is missing” or “Your PC needs to be repaired.” The displayed error code can help identify the failure, but it does not by itself prove the cause.

Common causes include an interrupted update, disk or file-system problems, changes to partitions, a failed storage device, or firmware settings that now point to the wrong boot device. A loose or newly connected external drive can also alter which device the computer tries first. Avoid assuming that every BCD message calls for rebuilding the store: some failures are caused by the drive or its connection, and repair commands cannot fix failing hardware.

Start with low-risk checks

Turn the computer off and disconnect USB storage, memory cards, external drives, and discs that are not needed to start it. Leave essential keyboard, mouse, and display connections in place, then restart.
If the error began after a hardware change, check that the internal drive is connected securely, if you can do so safely and without voiding a warranty. For a laptop or unfamiliar system, consult the manufacturer or a repair professional rather than opening it.
Enter the computer’s UEFI or BIOS setup using the key shown during startup, often displayed briefly on screen. Check whether the internal Windows drive is detected and whether Windows Boot Manager is selected as the first boot option. Menu names vary by manufacturer.
Exit without changing unrelated settings. Do not switch between UEFI and Legacy/CSM boot modes casually: Windows installations are configured for a particular boot mode, and changing it can make a working installation unbootable.

If the drive is not detected, repeated software repair attempts are unlikely to help. Check manufacturer guidance for drive diagnostics or seek service. If the drive contains important data, prioritize recovery or backup before attempting repairs that write to it.

Use Windows Startup Repair

Startup Repair is the safest first Windows repair because it checks common startup problems without requiring you to type disk commands. To open the recovery tools, start the computer from Windows installation or recovery media, or use the recovery environment if it appears automatically after failed starts. On installation media, choose the language and keyboard settings, then select Repair your computer rather than Install now.

Go to Troubleshoot > Advanced options > Startup Repair.
Select the Windows installation if prompted, and provide account details if requested.
Wait for the check to finish, then restart and see whether Windows starts.

Recovery menus can differ between Windows versions and device makers. If Windows asks for a BitLocker recovery key, retrieve it from the place where it was saved or from the organization that manages the device. Do not clear the TPM or change firmware security settings as a workaround; those actions can complicate access to encrypted data.

Rebuild boot files from recovery tools

If Startup Repair does not work, an experienced user can use Command Prompt in Troubleshoot > Advanced options > Command Prompt. Drive letters in recovery mode may differ from the letters seen in Windows, so first identify the Windows volume rather than assuming it is C:. You can check volumes with diskpart, then list volume, and exit DiskPart with exit. Do not run commands that delete, format, or repartition volumes.

Find the volume containing the Windows folder by checking likely letters with a command such as dir D:\Windows, substituting another letter as needed. If the folder is present, the UEFI boot files may be rebuilt with bcdboot D:\Windows, replacing D: with the actual Windows volume letter. BCDBoot copies boot files from the Windows installation and creates or repairs the system boot environment. On some systems, especially with multiple Windows installations or unusual partition layouts, specifying the system partition may be necessary; selecting the wrong partition can make startup worse. If you are unsure which volume is the EFI system partition, stop and get device-specific help rather than guessing.

Older guides often recommend bootrec /fixmbr, bootrec /fixboot, or bootrec /rebuildbcd. These commands are not a universal fix. Their usefulness depends on the boot mode and disk layout, and some may return errors on UEFI systems. Do not repeatedly run commands from unrelated tutorials or change partition attributes without understanding the layout.

Check the disk and protect your files

A damaged file system or failing storage device may prevent Windows from reading boot files. If the drive is detected but Windows still will not start, consider a manufacturer-provided diagnostic or professional assessment. A disk check can help identify file-system issues, but repairs write changes to the drive; if the disk is clicking, disappearing, unusually slow, or contains irreplaceable files, stop using it and seek data-recovery advice before running repair utilities.

Once Windows starts, back up important files promptly. Then review recent updates or hardware changes and use Windows recovery options only after confirming that a backup exists. System Restore may help if a recent change caused the failure, but it is not a substitute for a file backup. Resetting or reinstalling Windows can remove apps and, depending on the option chosen, personal files; read each screen carefully and do not proceed until you understand what will be retained.

Common mistakes and when to get help

Using the wrong drive letter: Recovery mode assigns letters independently, so verify the Windows folder first.
Changing boot mode at random: UEFI and Legacy/CSM settings should match how Windows was installed.
Formatting the EFI partition: It contains startup files and is not a general-purpose empty partition.
Assuming a rebuild restores data: BCD repair addresses startup configuration; it does not recover deleted personal files or repair a physically failing disk.

Contact the computer maker or a qualified technician if the drive is not detected, diagnostics report hardware errors, the disk layout is unclear, encryption recovery is unavailable, or the computer contains data that cannot be replaced. On a work or school device, ask the organization’s IT administrator before changing startup settings.

Frequently Asked Questions

Can I fix the BCD error without reinstalling Windows?
Often, yes. Check the boot order and run Startup Repair first. If needed, rebuilding boot files with the correct Windows and system partitions may restore startup. Reinstallation is usually a later option, not the first step.

Will rebuilding BCD delete my files?
Rebuilding boot files is intended to repair startup configuration, not erase personal files. However, choosing the wrong partition or running destructive commands can cause data loss, so verify the disk layout and back up important data whenever possible.

Why does Startup Repair say it couldn’t repair my PC?
It may not be able to fix the underlying issue, such as a failing drive, damaged system files, an unusual partition layout, or incorrect firmware settings. Note any log or error details and avoid repeating the same repair without checking the cause.

Is this error caused by a virus?
It is not enough to conclude that the computer has malware. Hardware, file-system, partition, and firmware issues are also common explanations. Restore normal startup first, then use reputable security tools if there are other signs of infection.

What if the computer asks for a BitLocker recovery key?
That means the encrypted Windows drive needs its recovery key to unlock. Look for the saved key or contact the organization that manages the device. Do not erase or reset the drive if you need files that you cannot restore elsewhere.

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

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