The Boot Configuration Data (BCD) file is not stored in a single standard directory on your hard drive like typical documents. Instead, it resides within a hidden system partition called the EFI System Partition (ESP) or, on older systems, in the root of the C: drive. Understanding this location is critical for troubleshooting boot failures and repairing Windows startup issues.
Understanding the BCD Store Structure
To locate the BCD file, you must first understand that modern Windows installations use a UEFI firmware interface rather than the legacy BIOS. In this architecture, the boot configuration is stored in a binary store known as the BCD store. This store is physically located on the EFI System Partition (ESP), which is a small FAT32-formatted partition created during the initial Windows installation.
On systems using the traditional BIOS/MBR setup, the BCD data might be found directly in the
\Boot\BCD path on the active system drive, typically
C:\. However, even in these cases, the file is marked as hidden and read-only to prevent accidental modification. For the vast majority of users running Windows 10 or Windows 11 on UEFI hardware, the file is strictly contained within the ESP.
Locating the File via Command Prompt
The most reliable way to find the exact drive letter assigned to the ESP is by using the DiskPart utility. This tool allows you to view all partitions on your disk without needing third-party software. Follow these steps to identify the correct volume.
- Open the Start menu, type
cmd, right-click "Command Prompt," and select "Run as administrator."
- Type
diskpart and press Enter to launch the disk management tool.
- Enter
list vol to display all volumes on your system.
- Look for a volume with a size between 100 MB and 500 MB that is formatted as FAT32. This is usually the EFI System Partition.
Once you have identified the volume number of the ESP, you can assign it a temporary drive letter to access its contents. Type
select vol X (replacing X with the volume number) followed by
assign letter=S. Now, open File Explorer and navigate to
S:\EFI\Microsoft\Boot\. Inside this folder, you will find the
BCD file. After verifying its presence, remember to remove the drive letter by returning to the command prompt and typing
remove letter=S to maintain security.
For more complex boot repair scenarios involving corrupted stores, see our guide on
BCD won't let repair boot Windows & can't boot Linux distro.
Accessing the BCD File in Legacy Systems
If you are working with an older computer that uses MBR partitioning and BIOS firmware, the location differs slightly. In this scenario, the BCD file is typically located at
C:\Boot\BCD. Because this file is hidden by default, you need to enable the viewing of hidden items in File Explorer.
Navigate to the View tab in File Explorer and check the box for "Hidden items." Then, go to the root of your C: drive and enter the
Boot folder. You should see the
BCD file there. It is important to note that modifying this file manually using a text editor is dangerous and often impossible because it is a binary file managed by the
bcdedit command-line tool.
Why the Location Matters
Knowing where the BCD file lives helps when diagnosing why Windows fails to start. If the file is missing or corrupted from the ESP, the system will display errors like "No Boot Device Found" or "Boot Manager Missing." In such cases, simply copying a backup file may not suffice; you often need to rebuild the store using commands like
bcdboot c:\windows.
Additionally, if you are dual-booting with Linux, the BCD file's location is crucial for configuring the GRUB bootloader or ensuring that Windows appears correctly in the boot menu. Misidentifying the partition can lead to overwriting critical boot data. For users needing to adjust how their system initializes hardware before loading the OS, understanding the boot chain is essential, much like knowing how to
boot into UEFI firmware via command line.
Best Practices for Backup
Before making any changes to the BCD store, always create a backup. Open an elevated Command Prompt and run the command
bcdedit /export C:\BCD_Backup. This creates a copy of the current store on your C: drive. If something goes wrong during a repair, you can restore it using
bcdedit /import C:\BCD_Backup. Never attempt to edit the file in the ESP directly unless you are following a specific Microsoft support procedure, as incorrect edits can render the system unbootable.
Frequently Asked Questions
Can I delete the BCD file to fix boot issues?
No, deleting the BCD file will prevent Windows from starting. The file contains essential instructions on where the operating system kernel is located and which drivers to load. Deleting it requires a full reinstall or a repair install from installation media.
Is the BCD file visible in normal File Explorer mode?
No, the BCD file is hidden by default due to its system-critical nature. You must enable "Hidden items" in the View settings or use the Command Prompt to access it safely. Even then, you typically need administrative privileges to view its properties.
What happens if the BCD file is corrupted?
A corrupted BCD file results in boot failure, often showing error codes like 0xc000000f or 0xc0000225. You will likely be unable to access Safe Mode or Advanced Startup options. Repairing it usually involves using the Windows Installation Media to run automatic repairs or manually rebuilding the store.
Does moving my C: partition affect the BCD location?
Moving the C: partition does not move the BCD file itself, as the BCD resides on the separate EFI System Partition. However, changing the drive letter of the system partition can break references within the BCD store. If you move partitions, you may need to update the BCD entries using
bcdedit to reflect new paths. See
how to move C partition to another disk for detailed steps.
Can I edit the BCD file with Notepad?
No, the BCD file is a binary database, not a plain text file. Opening it in Notepad will result in garbled characters and will not allow you to make meaningful changes. You must use the
bcdedit command-line utility or the Graphical User Interface tools provided by Windows to modify boot settings.