Windows command guide

Fix bootrec /fixboot access is denied

The old bootrec /fixboot step often fails with access denied on modern UEFI systems. In many cases the more useful fix is rebuilding boot files onto the EFI partition with bcdboot instead.

This guide is written around the specific symptom-command match for fix bootrec /fixboot access is denied, not as a generic dump of terminal lines. That makes the page more useful for real troubleshooting and reduces the chance of running the wrong repair step.

Reviewed guide Updated 2026-04-21

Windows Recovery Environment Command Prompt

diskpart
list vol
select vol <EFI_VOLUME>
assign letter=S
exit
bcdboot C:\Windows /s S: /f UEFI

Best place to run it

Windows Recovery Environment Command Prompt is the right execution context for this page. Even when elevation is not always required, using the right shell prevents syntax mistakes and makes the output easier to trust.

Fast repair workflow

Start from the exact symptom on this page: bootrec /fixboot returns Access is denied
Run the startup recovery line exactly as shown: diskpart list vol select vol <EFI_VOLUME> assign letter=S exit bcdboot C:\Windows /s S: /f UEFI.
This workflow is tuned for this repair, so avoid mixing it with unrelated repair commands too early.
Re-check boot state with BCD or recovery info instead of repeating the same boot command blindly.
If startup still fails, move to partition, file-system, or recovery-media diagnostics instead of stacking more write operations.

Recovery command sequence

Use this sequence when you want the page command in a cleaner, step-by-step recovery block.

:: Run these lines from Windows Recovery Environment when the guide calls for it
@echo off
echo Starting recovery command sequence...
diskpart
list vol
select vol <EFI_VOLUME>
assign letter=S
exit
bcdboot C:\Windows /s S: /f UEFI
echo.
echo Review the output and restart only after the command sequence finishes.
pause

Verification commands after the repair

These follow-up commands help you check whether the repair actually changed the Windows state that matters, instead of assuming success from a single line.

bcdedit /enum
reagentc /info

What problem this command is trying to solve

This page targets boot repair sessions where the classic fixboot command is blocked even though the machine still has a valid Windows installation to copy boot files from.

bootrec /fixboot returns Access is denied.
You are already inside Windows Recovery Environment.
The system uses UEFI boot rather than old BIOS-style booting.

How the command works

diskpart helps identify and mount the EFI system partition, and bcdboot then copies fresh boot files from the Windows installation to that partition.

When it makes sense to run it

Use it when you need to repair UEFI boot data and fixboot is not cooperating.

Before you run this command

Open the shell that matches diskpart list vol select vol <EFI_VOLUME> assign letter=S exit bcdboot C:\Windows /s S: /f UEFI before you paste it.
Confirm that the symptom really matches this guide, especially if you are seeing signs such as: bootrec /fixboot returns access is denied.
Write down the exact startup or recovery message before you change boot-related data.

What result to expect

After running diskpart list vol select vol <EFI_VOLUME> assign letter=S exit bcdboot C:\Windows /s S: /f UEFI, compare the result against the symptom that brought you here. The most useful checkpoint is whether bootrec /fixboot returns access is denied becomes less frequent, changes form, or produces a clearer error message. A command page is stronger when it helps you verify a real change instead of just assuming the line must have worked.

How to verify that it worked

The best verification step after diskpart list vol select vol <EFI_VOLUME> assign letter=S exit bcdboot C:\Windows /s S: /f UEFI is to repeat the action that previously triggered the problem. If you are already inside windows recovery environment still appears in exactly the same way, the command probably was not the whole answer and you should move to the next targeted check instead of assuming the page is finished.

Shell and execution context

This command usually does not need a full elevated repair context, but it still works best when you run it in the shell it was written for and read the output carefully.

Before you run it

Selecting the wrong volume in diskpart is risky. Confirm which partition is the EFI system partition before assigning a drive letter.

When this is probably the wrong fix

This is not the right first fix for a simple slow boot caused by startup apps alone. Use it when Windows cannot start properly, recovery keeps appearing, or boot data itself looks damaged.

What to do if it does not help

If diskpart list vol select vol <EFI_VOLUME> assign letter=S exit bcdboot C:\Windows /s S: /f UEFI does not improve bootrec /fixboot returns access is denied, move to the next repair step that matches the same symptom family instead of piling on random commands. The best follow-up depends on whether the failure is mainly about startup, recovery, or boot configuration.

Frequently asked questions

Should I use diskpart list vol select vol <EFI_VOLUME> assign letter=S exit bcdboot C:\Windows /s S: /f UEFI for this exact Windows symptom?

Use it when the behavior on your PC lines up with the repair target on this page: This page targets boot repair sessions where the classic fixboot command is blocked even though the machine still has a valid Windows installation to copy boot files from.

What should I check right after diskpart list vol select vol <EFI_VOLUME> assign letter=S exit bcdboot C:\Windows /s S: /f UEFI?

Check whether the original trigger still reproduces the same failure. For this page, a useful checkpoint is whether bootrec /fixboot returns access is denied becomes less frequent, changes form, or points you toward a more specific next step.

When should I not rely on diskpart list vol select vol <EFI_VOLUME> assign letter=S exit bcdboot C:\Windows /s S: /f UEFI alone?