Skip to content
Published 6 avril 2016

Désolé, cet article est seulement disponible en Anglais Américain. Pour le confort de l’utilisateur, le contenu est affiché ci-dessous dans une autre langue. Vous pouvez cliquer le lien pour changer de langue active.

You have a problem: you have installed an operating system and you have carelessly deleted your EFI partition!

The Fix

Start up your dilapidated computer with the USB or DVD Windows 10 recovery media in the system.You want to get to the Advanced options screen so that you can open the beloved command prompt.

When the computer boots off the recovery media, pick the Troubleshoot option

enter image description here

Then choose Advanced Options

enter image description here

and head on over to the Command Prompt.

enter image description here

The computer should reboot and you will see a windows that prompts you to enter some statements. And then we will begin put some commands into it.

We’re going to use the built in partitioning tool called diskpart to confirm that:

We have all the right partitions
EFI partition is formatted correctly.
In the black screen that looks like a dark abyss, type:

diskpart

enter this command to watch how many disks are on your drive.

list disk

choose the right using drive. e.g., I have three Drives installed and the 1TB Seagate Drive is which I am operating on and its code is 0, and enter this command:

sel disk 0

Now that the first disk is selected we need to view all the partitions

list vol

enter image description here

Verify that the EFI partition is using the FAT32 file system then select the volume and assign a drive letter to it.

Since i’m using Windows 8 from a VirtualBox image you won’t see the FAT32 partition on the screenshot above; but on yours you can select it by noting the Volume Number. Don’t worry, it’s quite easy to distinguish the differences between your computer and mine even if I am not showing an actually narrative picture of mine.

1. Assign the Drive Letter

Let’s say your EFI partition is on Volume 3, the next thing you would type is:

sel vol 3

Then assign an arbitrary drive letter to the parition. Let’s use v.

assign letter=v:

You should see a message saying: DiskPart successfully assigned the drive letter or mount point.

Exit the diskpart tool by typing:

exit

You should still be in the command prompt but outside of the DISKPART> prompt.

2. Repair the Boot Record

We need to repair the boot record. We can pull that off like so:

cd /d v:\EFI\Microsoft\Boot\
bootrec /fixboot

The CD command tells the command line interpreter to change the directory to the volume label that has the EFI boot record.

Then the bootrec /fixboot command attempts to repair the selected volume.

Alright, still with me?

3. Rebuild the BCD store

Now we need to recreate the Boot Configuration Data (BCD) store, so let’s backup the existing store first

Type:

ren BCD BCD.old

Now that we backed it up, let’s recreate the BCD store:

bcdboot c:\Windows /l en-us /s v: /f ALL

BCDBoot is little tool that lets you manage the system partition files. In plain english, this command says:

Hey Windows, I’m going to use C:\Windows as the source for copying all my boot-environment files and I’m going to use the English locale and select the volume letter that begins with v:

The /f ALL thingy updates all the BIOS settings.
Now remove the recovery media and reboot and you should be all set.

Reference: How to repair the EFI Bootloader in Windows 10

Source 

2 Comments

  1. Alex Alex

    Thanx allot! that was amazing!

    I´ve tried to merge part c with d in order to gain space on c with easeus and i ended up with the c\windows\system32\logfiles\Srt\SrtTrail.txt windows 10 error. After many tries and many errors like error 0x80070057 i’ve tried your fix and even thow i’ve got bootrec /fixboot acces denied i’ve continued with your command lines and it worked !

    THX

  2. Hi alex.

    please apply this instruction

    Windows 10 Installation Media:

    Insert the Media (DVD/USB) in your PC and restart.
    Boot from the media.
    Select Repair Your Computer.
    Select Troubleshoot.

    Choose Command Prompt from the menu:
    Type in the command:

    Diskpart

    Type in the command:

    List disk (Note which disk is your Boot drive number mine is 0)

    Type in the command:

    Sel disk 0

    Type in the command:

    List vol (Note which volume is the EFI partition mine is 4)

    Type in the command:

    Sel vol 4

    Type in the command:

    assign letter=V:

    Type in the command:

    Exit

    Type in the command:

    V:

    After you have assigned a drive letter Using Diskpart You can format the EFI partition:

    Example: if you assigned a letter V to the partition the command would be:

    format V: /FS:FAT32

    After the format you need to recreate the EFI directory structure with the command:

    MD \EFI\Microsoft\Boot

    Then change to the Boot directory with:

    cd /d V:\EFI\Microsoft\Boot\

    Then run:

    bootrec /FixBoot

    Finally run:

    bcdboot c:\Windows /l en-us /s V: /f All

Laisser un commentaire

Votre adresse de messagerie ne sera pas publiée. Les champs obligatoires sont indiqués avec *