Complete guide to using bootrec.exe to rebuild the Boot Configuration Data (BCD) in Windows

Troubleshooting boot issues in Windows is one of the most stressful situations any user or technician can face. When the system displays messages like Missing Boot Configuration Data or BCD file errors, it is essential to understand how the boot process works and how to use the right tools to recover.

In this article, you will find a comprehensive and up-to-date guide on how to use the bootrec.exe utility and the most effective techniques for rebuilding the Boot Configuration Data (BCD) in different versions of Windows. Here we detail not only the basic steps, but also advanced methods and workarounds when simple solutions don't work. Get ready to learn how to bring your computer back to life in less time than you imagine.

What is BCD and what is its importance in Windows?

El Boot Configuration Data (BCD) or Boot Configuration Data is a firmware-independent database in which Windows stores critical information for locating the operating system at boot time. Without a full BCD, Windows simply won't boot., displaying errors that can range from "Missing BCD file" to codes like 0xc00000f o 0xc0000098.

This file is usually located in \Boot\BCD in traditional BIOS/MBR systems, or in /EFI/Microsoft/Boot/BCD on UEFI systems. Its corruption can be due to unexpected power outages, disk failures, partition extensions, errors after installing another operating system, virus attacks or system changes hardware.

Why can the BCD fail? Main causes and symptoms

The BCD can be affected by multiple factors:

• Changes to disk partitions: Extending the active partition or manipulating partitions may destroy file consistency.
• Sudden shutdowns or power outages: They are a common cause of corrupted BCD files.
• Hardware errors: Damaged sectors on the hard drive can make the file unreadable.
• Malware or virus: Some types of malware target boot records and configuration files.
• Installation of OS additional: Installing an older version of Windows after a newer version always requires manual intervention on the BCD.

Common symptoms are:

• Blue screen critical error after turning on the equipment.
• Message type "Boot configuration data is missing" or similar.
• Error codes such as 0xc000000f, 0xc0000034, 0xc00000e9, 0xc0000098, among others, indicating problems with the BCD file.
• The computer won't get past the initial Windows logo or enters an automatic repair loop.

What is bootrec.exe and what is it used for?

bootrec.exe is a powerful command-line utility included in the Windows Recovery Environment (Windows RE). It allows you to repair several critical boot components, especially the MBR (Master Boot Record), boot sector and, of course, the BCD databaseIts use is essential when the automatic boot process fails to restore the system.

Main bootrec.exe options and when to use them

When running the bootrec.exe tool, you can use the following switches depending on the situation:

• / FixMbr: Overwrites the MBR on the system partition, useful if you suspect the Master Boot Record is corrupted or has been altered by malware.
• /FixBoot: Writes a new boot sector to the system partition. Use this when the boot sector is damaged or replaced by a non-standard one. More details on how to analyze and repair Windows startup.
• / ScanOs: Scans all disks to detect Windows installations that have not been added to the BCD and lists them for possible inclusion.
• / RebuildBcd: Scans all disks and allows you to select which installations to add, completely rebuilding the BCD store.

It's worth noting that while the automatic option usually works, you may sometimes need to take additional steps to delete, export, or create the BCD store from scratch. For a more in-depth look at these steps, we recommend consulting the Complete guide to manipulating BCD in Windows.

How to access the Windows Recovery Environment (Windows RE)

In order to use bootrec.exe you must boot the computer from a Windows installation media (USB or DVD):

1. Insert the USB or DVD and restart the computer.
2. Press a key to boot from media when prompted.
3. Set the language, time, currency and keyboard and click on Next.
4. Choose Repair equipment (usually in the lower left corner).
5. Access the menu Solve problems and then to Advanced.
6. Choose Symbol of the system.

Step-by-step guide to repair and rebuild BCD with bootrec.exe

In the command console, follow the procedure below, pressing Enter after each line:

1. bootrec / fixmbr
2. bootrec / fixboot
3. bootrec / scanos (This command will search for unregistered Windows installations in the BCD)
4. bootrec / RebuildBcd (when finished, type "A" to add the detected installation to the boot list)

Restarting after this process usually fixes most BCD errors. If the problem persists, you may need to delete, rename, and recreate the BCD manually. For this, you can also consult the .

Restore BCD File from Scratch: Advanced Method

If you still get the error after applying the basic commands, perform a clean rebuild:

1. Bcdedit /export C:\BCD_Backup (to create a backup of the current BCD).
2. attrib c:\boot\bcd -s -h -r (remove system, hidden, and read-only attributes).
3. ren c: \ boot \ bcd bcd.old (renames the current BCD).
4. Now repeat the commands:
   • bootrec / fixmbr
   • bootrec / fixboot
   • bootrec / RebuildBcd

These steps force the creation of a completely new BCD store, ruling out any previous corruption. Remember to check the actual letter of your system partition using diskpart if it is not C: in your case.

Alternative solutions: BCD creation and advanced management

If even the manual reconstruction method does not solve the problem, there are other additional techniques:

• Create the BCD with bcdboot: Execute bcdboot c:\windows (setting the letter to your actual installation directory). This command copies boot files and creates the BCD file on the active partition. You can learn more in the section How to boot Windows in safe mode.
• Manage the BCD with bcdeditAdvanced commands with bcdedit allow you to customize boot loader entries, set active partitions, change the timeout, and configure the operating system boot order. For a complete guide, visit .

What to do if Bootrec /Fixboot gives access denied?

An increasingly common error in recent versions of Windows is that bootrec / fixboot throw a message of "Access denied"This is usually due to incompatibilities with the installation media version, especially with build 1709 on Windows 10. Some possible solutions include:

• Test the process with a oldest system image (for example, build 1703).
• Manually recreate the EFI partition with diskpart and apply the correct commands to copy the boot files.
• Use third-party tools such as EASEUS Partition Master o AOMEI Partition Assistant, which facilitate the reconstruction of MBR and BCD visually.
• run the auto repair from the recovery environment as an alternative.

Third-party tools for BCD and MBR repair

There are utilities such as EASEUS Partition Master y AOMEI Partition Assistant These tools allow you to create bootable media from another working computer and then repair the BCD and MBR on the problematic PC. These tools are particularly useful if you can't access the command prompt or want to speed up the process in just a few clicks.

Additionally, some versions even allow you to rebuild the MBR on disks of different types (MBR or GPT), identify problems in the boot partition, and perform automatic backups to prevent future serious errors during boot.

Complementary solutions and practical advice

• Mark the correct partition as active: : Often, Windows won't boot because the boot partition is inactive. Use diskpart to identify and activate the correct partition ().
• Back up critical files before operating: It is highly recommended, if possible, to save your data before manipulating partitions or overwriting the BCD.
• Update the installation media: Always use the latest version of Windows installation media to avoid incompatibilities.
• Avoid sudden changes to disk partitions: Before enlarging, reducing or forma tear partitions, performs a full system backup.
• Use reliable backup softwareTools like AOMEI Backupper allow you to automate system image creation and easily restore them in the event of boot failures.

Frequently Asked Questions About BCD Reconstruction

• Where is the BCD file located?
  In systems BIOS traditional, is located in the folder \Boot\BCD of the active partition. On UEFI systems, it is in the EFI partition in the path /EFI/Microsoft/Boot/BCD.
• Can the BCD be edited manually?
  Yes, with the tool bcdedit, although it is advisable to do so with previous experience and in specific cases.
• What errors does a corrupt BCD generate?
  Messages like “Your PC needs to be repaired,” errors 0xc000000f, 0xc0000034, “BOOTMGR is missing,” or infinite repair loops.
• What should I do if the commands don't fix the problem?
  Try manual methods, third-party utilities, or consult a professional. Sometimes, physical damage to the drive makes recovery impossible without a replacement.

Rebuilding the BCD and repairing boot errors in Windows requires a combination of patience, technical knowledge, and the proper use of utilities like bootrec.exe and specialized tools. Following an organized strategy and understanding all available resources allows you to restore boot performance even in the most complicated cases, reducing the risk of data loss and restoring peace of mind to the user.

Related article:

Complete Guide to BCD Manipulation in Windows: Recovery, Repair, and Advanced Options

Isaac

Passionate writer about the world of bytes and technology in general. I love sharing my knowledge through writing, and that's what I'll do on this blog, show you all the most interesting things about gadgets, software, hardware, tech trends, and more. My goal is to help you navigate the digital world in a simple and entertaining way.