Systems running Windows 11 may suddenly refuse to boot, displaying the error message bootrec /fixboot access is denied when attempting repairs in the Windows Recovery Environment. This error typically blocks essential recovery commands, leaving the computer stuck in an unbootable state due to issues with the EFI partition, boot configuration data, or disk integrity. Addressing the problem requires a methodical approach to restore bootloader access, repair file system structures, and ensure Windows can start up normally.

Repair the EFI Partition and Rebuild Boot Files

Assigning a drive letter to the EFI System Partition (ESP) and rebuilding the Boot Configuration Data (BCD) is the most effective solution for resolving the "access is denied" error. The EFI partition stores critical bootloader files, and when it's missing a drive letter or contains corrupted data, Windows cannot execute repair commands successfully.

Step 1: Insert your Windows 11 installation USB or DVD and boot the computer from this media. If needed, adjust the boot order in your BIOS or UEFI settings so the installation media loads first.

Step 2: On the Windows Setup screen, select your language and preferences, then click Next. In the bottom left, choose Repair your computer to enter the Windows Recovery Environment.

Step 3: Navigate to Troubleshoot > Advanced options > Command Prompt to open a command prompt window.

Step 4: Use diskpart to identify and assign a drive letter to the EFI partition:


diskpart
list disk
select disk 0
list volume
select volume #   (replace # with the number of the EFI partition, usually labeled as FAT32 and around 100-260MB)
assign letter=V:  (replace V with any unused drive letter)
exit

This process makes the EFI partition accessible for repairs.

Step 5: Format the EFI partition to ensure it is clean and ready for new boot files. Type:


format V: /FS:FAT32

Confirm the operation when prompted. Formatting removes all existing boot files from the partition, which is necessary if corruption is suspected, but will require rebuilding the bootloader in the next steps.

Step 6: Rebuild the Boot Configuration Data by copying new boot files from your Windows installation to the EFI partition:


bcdboot C:\Windows /s V: /f UEFI

This command copies the required boot files to the EFI partition and configures the system to boot in UEFI mode. Make sure C:\Windows matches the location of your Windows installation. If your system drive uses a different letter in WinRE, adjust accordingly.

Step 7: Close Command Prompt and restart your computer. Remove the installation media. The system should now boot normally, with the "access is denied" error resolved.

Use Windows Startup Repair Tool

The built-in Startup Repair tool can automatically diagnose and repair common bootloader issues, including those that prevent bootrec /fixboot from running. This tool is especially helpful when the cause of the error is unclear or when manual repairs fail.

Step 1: Boot from your Windows installation media and, after selecting your preferences, click Repair your computer.

Step 2: Select Troubleshoot > Advanced options > Startup Repair.

Step 3: Choose the Windows installation you want to repair. The tool will scan for issues and attempt to repair them automatically. This process may take several minutes and require a restart.

Startup Repair addresses many typical boot problems but may not resolve the "access is denied" error if the EFI partition is missing or corrupted. If the issue persists, proceed with manual EFI partition repairs.

Run CHKDSK to Repair Disk Errors

File system corruption or bad sectors can prevent access to the bootloader, resulting in the "access is denied" message. Running the Check Disk utility identifies and repairs these issues, improving the reliability of subsequent repair commands.

Step 1: Boot into the Windows Recovery Environment as described previously and open Command Prompt.

Step 2: Run the following command, replacing C: with your system partition if necessary:


chkdsk C: /r

This command scans the partition for errors and attempts to repair them. Allow the scan to complete fully before restarting.

After CHKDSK finishes, retry the bootrec /fixboot command or proceed with EFI partition repairs if needed.

Rebuild the Master Boot Record (MBR) and BCD

On systems using legacy BIOS with MBR partitioning, or when BCD corruption is suspected, repairing the MBR and rebuilding the BCD can restore boot functionality. This approach is particularly relevant for older hardware or systems upgraded from Windows 10.

Step 1: Open Command Prompt from the Windows Recovery Environment.

Step 2: Enter the following commands one by one, pressing Enter after each:


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

These commands repair the master boot record, write a new boot sector, scan for Windows installations, and rebuild the boot configuration database. If bootrec /fixboot still returns "access is denied," ensure the EFI partition is accessible and repeat the earlier steps to assign a drive letter and rebuild boot files.

Check and Adjust BIOS/UEFI Boot Mode Settings

Boot mode and partition style mismatches can block access to the bootloader. Windows 11 requires UEFI firmware with a GPT partition style. If your system is set to legacy BIOS or the partition style does not match the firmware mode, startup errors and repair failures occur.

Step 1: Restart your computer and enter the BIOS or UEFI setup (commonly by pressing F2, F12, Del, or Esc during startup).

Step 2: Locate the boot mode settings. For Windows 11, ensure UEFI mode is enabled and Legacy or CSM mode is disabled.

Step 3: Save changes and exit. Attempt to repair the bootloader again using the previous methods.

Restore from Backup or Reinstall Windows

If none of the above methods restore boot functionality and bootrec /fixboot access is denied persists, restoring a recent system backup or performing a clean installation of Windows 11 may be necessary. Always back up important data before reinstalling, as this process can overwrite files on your system partition.

To restore from a backup, use your preferred backup software's recovery media to boot the system and follow the on-screen instructions to restore your system image. If reinstalling, follow the Windows installation prompts after booting from official installation media, selecting the existing Windows partition for installation to preserve the disk structure when possible.

Restoring the EFI partition, repairing boot files, and ensuring correct firmware settings directly resolves the "bootrec /fixboot access is denied" error on Windows 11. Regular backups and periodic disk checks help prevent future bootloader issues and data loss.