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FolderRisk: Do not touch

EFI \EFI

The \EFI folder of the EFI System Partition (ESP, no drive letter): it holds the UEFI boot loaders for Windows and any other installed operating system.

Updated on By AltF4 Formation

What it’s for

\EFI is the root of the boot loaders on the EFI System Partition (ESP), the FAT32 partition that UEFI firmware reads before anything else. Windows puts its files in \EFI\Microsoft\Boot. A second operating system (Linux, for instance) adds its own folder, and \EFI\Boot holds the fallback loader that firmware runs when no boot entry is registered.

The ESP has no drive letter, so you will not see it in File Explorer or under C:\. In Disk Management it is the small “EFI System Partition” on the GPT disk. Its GPT partition type GUID is C12A7328-F81F-11D2-BA4B-00A0C93EC93B.

What it contains

  • Microsoft: the Windows folder, with Boot (boot manager and BCD store) and, depending on the setup, recovery resources.
  • Boot: the fallback loader, used mostly on installation media (bootx64.efi on 64-bit).
  • One folder per additional operating system or boot tool (Linux distribution, vendor utility).

BIOS/MBR equivalent

On an MBR disk booting in BIOS mode there is no ESP and no \EFI. The bootmgr file and the \Boot folder (with the BCD store) sit at the root of the active partition, often labelled “System Reserved”.

Risks and best practices

  • If \EFI\Microsoft\Boot is wiped or the ESP is reformatted, the PC no longer boots. Repair it from the recovery environment with bcdboot C:\Windows /s S: /f UEFI.
  • On a dual-boot machine, do not delete the other systems’ folders as “cleanup”: their boot entries would stop working.
  • Mount the ESP only for the duration of the task, then unmount it with mountvol S: /D.

Useful commands

Fenêtre de terminal
:: As administrator: mount the ESP as S:
mountvol S: /S


:: List the content (hidden items included)
dir S:\EFI /A /S /B


:: Unmount the ESP
mountvol S: /D


:: Boot entries stored in firmware
bcdedit /enum firmware
Fenêtre de terminal
# Partitions of the system disk: look for type System (the ESP)
Get-Partition -DiskNumber 0 | Select-Object PartitionNumber, Type, Size, DriveLetter

Folder contents

Folders 1

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