How to fix the bootrec fixboot access denied error in Windows

When your PC boots up with a nice blue screen and the message that Windows cannot access a required device (code 0xc000000e), the scare is considerable. Many users end up in the Windows Recovery Environment, open the Command Prompt, and try the command bootrec / fixboot And, to top it all off, they encounter another blow: “Access denied.”

This flaw is much more widespread than it seems, especially in systems with Windows 10 and Windows 11 that boot in UEFI mode and use an EFI partition. The good news is that, in most cases, the system can be recovered without a clean reinstall. In the following lines you will see, in detail, What exactly does bootrec /fixboot mean?, why the access denied error appears, and all known methods to repair the boot loader, EFI partition, MBR and BCD file, both with Windows tools and third-party utilities.

What is bootrec /fixboot and when is it used?

The command bootrec /fixboot is part of the bootrec.exe toolwhich runs from the Windows Recovery Environment (Windows RE). Its main function is to write a new starting sector in the system partition using a sector compatible with the installed Windows version: if you have Windows 7, generate a sector suitable for Windows 7; if it is Windows 10 or 11, one adapted to these versions.

This command is used when they appear classic startup errors: blue screens at startup, messages like “Bootmgr is missing”, “Boot device not found”, systems stuck in an automatic repair loop, or simply an error code like the 0xc000000e indicating that a necessary device is missing or cannot be accessed.

In those scenarios, official guides and many tutorials recommend launching a combination of commands such as bootrec /fixmbr, bootrec /fixboot and bootrec /rebuildbcd to rebuild the startup. The problem is that, since certain builds of Windows 10, when running bootrec / fixboot The message appearsAccess denied”, blocking the repair and leaving the user in exactly the same place: without a functional system.

It has been found that the error appears more frequently in installation media of Windows 10 1707, 1709 and 1803Whereas using an older installer (for example, Windows 10 1703) the same command may work without triggering the restriction. This has led Microsoft and the community to consider it, to a large extent, a bug or specific limitation of those installation mediaHowever, other factors such as the EFI partition, the BCD file, or the Secure Boot configuration also play a role.

Most common causes of the error “bootrec /fixboot access denied”

The "access denied" message doesn't appear for no reason. Several threads in the Microsoft Community and technical forums have been outlining the causes. most common causes what's behind the problem when running bootrec / fixboot:

• Problematic installation mediaWindows 10 installers in versions such as 1707, 1709, or 1803 have conflicting behavior with this command; with a 1703-based medium, the fault usually disappears.
• Damaged or missing drive letter EFI partitionIf the system partition (EFI) is corrupt, not properly formatted (it must be FAT32) or does not have a letter assigned, bootrec cannot write to it and returns access denied.
• Corrupt, missing, or inconsistent BCD fileWhen the boot configuration data (BCD) store is corrupted or misreferenced, the boot manager fails and some repair commands, including bootrec / fixbootThey fail.
• Boot configurations that need to be protectedIf there is a boot entry that the system considers should not be modified (for example, in environments with special workloads or dual boot), the manager may block the operation and display the famous "Access denied".
• Secure Boot, Fast Boot, and UEFI/Legacy mode are poorly combinedWith secure boot enabled, certain changes to the boot manager are limited; in addition, not all computers manage UEFI mode and Legacy mode the same way, which further complicates the process.

In practice, the error “bootrec fixboot access denied"It is usually the result of a mixture of these factors: a conflicting installation medium, a corrupted EFI partition, and a BCD that doesn't match the actual disk.Hence, the most effective solutions usually go in the direction of Recreate the UEFI structure, repair or recreate the BCD, and, if necessary, rebuild the MBR..

Method 1: Recreate the EFI partition and repair the UEFI bootloader

The most powerful way to tackle this problem is Recreate the UEFI structure and reconfigure the boot files From scratch. It's a slightly more technical procedure, but it gives the best results when the EFI partition is corrupted or Windows has "stuck" on the wrong disk, something very common in configurations with several SSDs or with dual boot (for example, Arch Linux + Windows).

This method starts from the Windows Recovery Environment, either because the system itself enters automatic repair after several boot failures, or because you have started from a Windows 10 or 11 installation USBFrom there, you can access the Command Prompt to work with diskpart and the boot commands.

The general outline of steps is as followsLocate the system disk, identify the EFI partition (usually small, 100 MB and in FAT32 format), assign it a drive letter, format it if necessary, and finally use bcdboot to load the correct boot files for your Windows installation into it.

Typical steps from the Recovery Command Prompt:

• Start diskpart.
• Use list disk to view the discs and select disk 0 (or another, if your system drive is not 0).
• Run list volume to find the EFI partition (usually 100 MB, System type, FAT32 format).
• Select that volume (select volume X) and assign it a letter, for example assign letter=N.
• Exit diskpart with exit.
• Write N: and press Enter to switch to that newly assigned drive.
• If the partition is damaged, format it with format N: /FS:FAT32.
• Rebuild the boot files with bcdboot C:\Windows /s N: /f UEFI (adjusting the letter C if your Windows installation is on a different drive).

After these steps, the UEFI charger is now regenerated with clean filesand in many cases, the command bootrec / fixboot Stop giving access denied errors, because there is now a healthy EFI partition to write to. Even if you don't use bootrec again, the system will usually boot normally simply with the repair performed by bcdboot.

Some advanced tutorials also cover the route EFI\Microsoft\Boot within the EFI partition and BCD files are renamed (for example, ren BCD BCD.old) to force a complete recreation of the boot configuration store. This is a useful maneuver when the BCD is particularly corrupt or full of obsolete references.

Method 2: Rebuild the MBR using Windows or third-party tools

Although in modern UEFI systems the EFI partition plays a central role, MBR (Master Boot Record) It remains important, especially on disks initialized in BIOS/Legacy mode or in certain mixed configurations. If the MBR is corrupted, Windows may refuse to boot, and tools like bootrec /fixboot encounter even more obstacles.

Windows includes the command bootrec / fixmbrdesigned precisely for rewrite the MBR without touching the partitionsFrom the Recovery Environment, simply open the Command Prompt and launch:

• bootrec / fixmbr

For users less familiar with the command line, there are third-party programs such as EASEUS Partition Master o AOMEI Partition Assistant that offer a graphic option of “Rebuild MBRThe typical process with these programs involves creating a WinPE boot disk or USBStart the problematic PC from that medium and, once inside the graphical interface, select the system disk and click on the MBR reconstruction function.

With EaseUS, for example, you usually:

• Create a bootable medium from another working PC using the option of “WinPE boot medium".
• Boot the faulty computer from that USB or CD/DVD, entering the BIOS and setting the removable drive as the first device.
• Within the program, go to Tools > Rebuild MBRSelect the disk where Windows is located and click on “Rebuild”.

AOMEI Partition Assistant follows a very similar philosophy: it allows you to create a bootable USB drive, check the disk surface for bad sectors, and, above all, repair the MBR automaticallyThese types of tools are very useful when you suspect that the problem is not only in the EFI partition, but in the basic boot structure of the disk.

Once the MBR has been rebuilt and the system boots successfully, it's a good idea to take this opportunity to check the disk and back up the most important data, because these types of failures are usually accompanied by physical or logical errors in the unit.

Method 3: Repair BCD and other boot errors with advanced commands

When access denied to bootrec /fixboot is accompanied by messages about damaged or missing BCD filesIt makes a lot of sense to directly attack the boot configuration store. Windows offers several commands for this, in addition to automatic options like Startup Repair.

From the Windows 10 or 11 installation media, you can go to Repair your computer > Troubleshoot > Advanced options > Command Prompt and execute the following sequence of commands, respecting the order:

• bootrec / RebuildBcd – scans disks for Windows installations and allows them to be added to the BCD.
• bootrec / fixmbr – rewrites the MBR without affecting the partitions.
• bootrec / fixboot – try writing a new boot sector to the system partition (this is where access denied usually appears if there are previous problems).

If “rebuildbcd” detects the Windows installation but the system still won't boot, the BCD may be too corrupted or there may be conflicting system partitions. In that case, many technicians opt for Rename the current BCD within the EFI partition and force the creation of a new one, combining the steps of method 1 with these bootrec commands.

Additionally, a disk check can be run with CHKDSKThis is very useful if you suspect bad sectors or logical errors in the Windows partition. Again, from the Recovery Command Prompt:

• chkdsk c: / r (replacing C with the actual drive letter of the partition where Windows is installed, which you can verify with diskpart > list volume).

the modifier /r It locates bad sectors and recovers readable information whenever possible. If the disk has physical problems, CHKDSK may take a while, but it's a highly recommended check before further troubleshooting the boot process.

In particularly rebellious cases, there are suites like EASEUS Partition Master that incorporate a specific function of “Boot repair"focused on the BCD and the components necessary for Windows to boot. The typical workflow is to create bootable media from another computer, boot the damaged PC with that media, and let the tool detect and correct boot configuration errors."

Method 4: Use Startup Repair and other automatic options

If you don't feel like dealing with too many command lines, Windows tools themselves include an option to Startup repair While not infallible, this function resolves many cases without requiring any further intervention. It analyzes the system, attempts to detect problems in the boot loader, the BCD, and certain critical files, and automatically applies corrections.

To access, you can start from a Windows installation media (USB or DVD) and, on the first screen, choose “Repair your computer” instead of “Install now”. Then, navigate through Troubleshoot > Advanced Options > Startup Repair and select the Windows installation you want to repair.

The assistant will perform a series of tests and, if necessary, modify boot files, repair the BCD, adjust secure boot options, and in some cases, prevent you from having to enter commands like bootrec /fixboot. However, if the problem is due to a bug in a specific version of the installation media (as is the case with certain Windows 10 builds), automatic repair may not be able to resolve it either.

If none of this works, Microsoft recommends, as a next step, Perform a complete repair of Windows 10 or 11 using the installation mediaThis is essentially an in-place reinstallation that attempts to keep your files and programs intact. This option also starts from the installation USB drive and, while more invasive than startup repair, it often resolves many problems, albeit at the cost of a little more time.

The Microsoft Community itself has been updating its answers as this bug has been ironed out. Moderators emphasize that it is crucial to have the operating system in the latest versioneither through Windows Update (Settings > Update & Security > Windows Update > Check for updates) or by downloading the latest update assistant from the official Windows 10 or Windows 11 download page.

Method 5: Adjust BIOS/UEFI, disable Fast Boot and Secure Boot

Another approach that has worked for many users involves tweaking certain BIOS/UEFI optionsespecially Fast Boot, Fast Power-On Self-Test, and Secure Boot. These features, designed to improve boot times and enhance security, can hinder some system repair processes.

The general process would be:

• Enter the BIOS/UEFI settings by pressing the indicated key when turning on the computer (usually F1, F2, Delete, Esc, etc., depending on the manufacturer).
• Locate in the tabs of Boat o Advanced the option of Fast Boot, Quick Power On Self Test or fast boot and deactivate it.
• Find the menu Secure Boot (usually in the Security or Boot tab) and temporarily disable it.
• Check the boot mode (UEFI, Legacy or UEFI/Legacy) and, if necessary, adjust to Legacy or a mode compatible with the type of installation you have on the disk.
• Save the changes using the "Save & Exit" option (usually F10) and allow the computer to restart.

Disabling Fast Boot and Secure Boot may to allow repair tools to write back to the EFI partition and in the bootloader. After resolving the issue, it's recommended to re-enable Secure Boot for security reasons, provided your configuration allows it.

On systems with multiple disks or dual boot configurations (for example, a primary SSD with Windows and another with Linux, or even a third empty SSD that has been used as a testing medium with tools like balenaEtcher), it is worth checking the BIOS the boot orderIt is relatively common that, after connecting or formatting a new SSD, the motherboard starts prioritizing that empty disk and the Windows loader gets "hanging" from it, which generates BSOD loops and seemingly inexplicable 0xc000000e errors.

Method 6: Check the disk and use data recovery software

When the system has gone through several startup failures, repair attempts, and possible power outages, the possibility of failure increases. disk errors or corrupted dataWe've already mentioned CHKDSK as a basic tool, but if, despite everything, you still can't get Windows to boot, another priority comes into play: rescue your files.

In that phase, data recovery utilities such as Recover Data Recovery They can be a very important lifeline. These applications allow you to create a Bootable USB To start a PC that won't boot, analyze drives and recover documents, photos and other important files before considering formatting or reinstalling from scratch.

The typical procedure with this type of program is:

• Install the software on another computer that is working properly.
• Select the option “Recover from a broken computer” or similar.
• Create a bootable USB drive (the program will warn you that it will be formatted, so it's a good idea to have a backup of any data on that memory).
• Configure the BIOS of the broken PC to boot from that USB drive.
• Once the recovery environment is loaded, use the program's interface to scan the disk from the system and copy the recoverable files to another secure external drive.

If, after trying all boot repair methods, you continue to experience errors such as 0xc000000e, changing blue screens, and “bootrec fixboot access denied”, the most sensible thing to do is save the data first And from there, consider a clean format, changing the installation media version if possible to avoid encountering the same bug again.

It's worth remembering that AOMEI Partition Assistant and other partitioning suites can also help you. diagnose the physical condition of the disc with surface testing, as well as allowing you to manage partitions, rebuild MBR and, in general, prepare the ground for an orderly reinstall if there is no other option.

Taken together, all these methods show that, although the error “bootrec /fixboot access denied” It seems very serious at first glance, but in reality it is usually linked to a combination of faulty installation medium, corrupted EFI partition, and inconsistent BCD which can be fixed with patience. Between recreating the UEFI with bcdboot, rebuilding the MBR, adjusting the BCD, running Startup Repair, tweaking the BIOS, and, if necessary, using third-party tools for advanced repair and data recovery, the chances of recovering the system without losing everything are quite high. That said, once you've gotten over the initial shock, it's worth updating Windows to a recent build, checking backups, and carefully noting these procedures so that the next boot error will catch you much more prepared.