Fix Boot Error 0xc000000e — and the UEFI "Access Is Denied" Trap

The fast answer. Error 0xc000000e ("A required device isn't connected or can't be accessed") means the Boot Configuration Data (BCD) points to a boot volume Windows can't reach. The standard advice is bootrec /fixboot — but on a UEFI/GPT machine that command returns "Access is denied". Don't fight it. The correct fix on UEFI is to rebuild the EFI boot files with bcdboot. From a Command Prompt in Windows Recovery:

diskpart
list disk
sel disk 0
list vol
sel vol <EFI-FAT32-vol#>
assign letter=S:
exit
bcdboot C:\Windows /s S: /f UEFI

C:\Windows is your Windows folder; S: is the EFI System Partition (the small ~100–500 MB FAT32 volume). Reboot and the error should clear.

Why "Access is denied" happens

On a UEFI/GPT system there is no boot sector to "fix" the way bootrec /fixboot expects on legacy MBR disks. The boot files live in a dedicated EFI System Partition (ESP) formatted FAT32. bootrec /fixboot often can't write there and reports Access is denied — that is expected behavior on UEFI, not a permissions bug to defeat. The right tool is bcdboot, which copies a fresh, correct set of UEFI boot files into the ESP and rebuilds the BCD entry.

Step-by-step fix (UEFI/GPT)

Step 1 — Open a Command Prompt in WinRE

Force three failed boots to reach Automatic Repair, or boot a Windows 10/11 install USB and choose Repair your computer. Then Troubleshoot → Advanced options → Command Prompt.

Step 2 — Confirm the disk is GPT and find the partitions

diskpart
list disk

An asterisk in the GPT column means the disk is GPT/UEFI (use this procedure). No asterisk means MBR/legacy — on MBR, bootrec /fixboot works and you don't have the access-denied trap. Then:

sel disk 0
list vol

Identify two volumes: your Windows volume (large, NTFS) and the EFI System Partition (small, ~100–500 MB, file system FAT32).

Step 3 — Assign a letter to the EFI partition

sel vol <EFI-FAT32-vol#>
assign letter=S:
exit

Pick a letter that isn't already in use (S: is just a convention). Note the letter of your Windows volume from list vol too — it is often C: in WinRE but can differ.

Step 4 — Rebuild the UEFI boot files with bcdboot

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

Replace C:\Windows with the real Windows path if your Windows volume isn't C:, and S: with the letter you assigned to the EFI partition. You should see "Boot files successfully created." Type exit and reboot.

Step 5 — If it still fails, scan for the install and check the disk

bootrec /scanos
bootrec /rebuildbcd
chkdsk C: /f /r

This re-detects the Windows installation and repairs file-system damage. If the EFI partition itself is missing or corrupt, bcdboot in Step 4 recreates the needed files there.

Data safety: bcdboot and bootrec only touch boot files, not your documents. But if this drive holds the only copy of data you can't lose, image the drive to a known-good external disk before running any repair — a disk that's already throwing boot errors may be physically failing, and chkdsk /r stresses weak sectors. Do not assign, format, or clean the wrong volume in diskpart; double-check volume numbers before each command.

GRAM tip: The steps above run in Windows Recovery, which is already on the broken PC. Once the machine boots again, plug in GRAM — a free portable repair toolkit that runs from a USB inside Windows — to check the disk's SMART health, read the boot config and event logs, and let its AI agent confirm the root cause so the error doesn't come back.

Download GRAM free See AI pricing →

FAQ

Can I fix this without a second working computer?

Yes. The fix runs entirely inside Windows Recovery on the broken PC — trigger it by forcing three failed boots, or boot from any Windows install USB. No second computer is required for the repair itself. (GRAM runs inside Windows rather than from boot media, so its role comes after: once the machine boots, it verifies disk health and confirms the root cause.)

Why does bootrec /fixboot say "Access is denied"?

Because the machine is UEFI/GPT. There's no legacy boot sector to fix; the boot files live in a FAT32 EFI System Partition that bootrec /fixboot can't write to. That's expected on UEFI. Use bcdboot C:\Windows /s S: /f UEFI against the EFI partition instead — that is the correct UEFI repair.

How do I know if my disk is UEFI/GPT or legacy/MBR?

In diskpart run list disk. An asterisk in the GPT column means GPT (UEFI) — use the bcdboot procedure. No asterisk means MBR (legacy), where bootrec /fixboot works normally and you won't hit the access-denied trap.

What does the /f UEFI flag do?

It tells bcdboot to write UEFI-firmware boot files (not BIOS/legacy ones) into the EFI System Partition you specified with /s. Omitting it can write the wrong firmware type and leave the machine unbootable, so always include /f UEFI on UEFI systems.