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Windows 8 can't start due to missing EFI partition

  1. #1


    Posts : 8
    Win 8

    Windows 8 can't start due to missing EFI partition


    I accidentally deleted the EFI partition, required to boot into my Win 8.1 installation - unbeknownst to me that EFI partition was on a different disk to where my Windows is located. To complicate matters the Windows install is on a RAID0 array.
    Windows repair using the original install media didn't work.
    EasyRE didn't detect the RAID0 drive.
    I saw various instructions on how to reconstruct the EFI partition, but they all assumed that the EFI partition is still there, which in my case it isn't.
    Does anyone know what I could try, or at the very least how I can get my data off that drive and re-install Windows?

      My System SpecsSystem Spec

  2. #2


    You can download EaseUS Partition recovery from:Download Free Partition Recovery Software - EaseUS Partition Recovery install it and run it
    Hope that helps.
      My System SpecsSystem Spec

  3. #3


    Posts : 1,121
    Windows 8.1 x64


    If you still have the space available for the EFI partition and no other unallocated space on the drive, you can use diskpart to recreate the EFI partition. You have to make sure and select the correct drive and then use the command below to create it. If you have other unallocated space, go ahead and format it, or you will need to add the size and offset information to the Create partition command.

    diskpart
    list disk

    select disk 0 <- use disk you want to add the partition to.
    create partition efi
    format quick fs=fat32


    Then you can use the bcdboot command to replace the boot files assuming the Windows partition is C: when you are in the Recovery system.

    bcdboot c:\windows

    I would not use EaseUS for any UEFI installation......but you could use one of the others to make space on the Windows drive for the EFI partition. This can be dangerous, however.
      My System SpecsSystem Spec

  4. #4


    Posts : 879
    Windows 10


    If you have deleted the System Reserved partition, not the EFI System partition, then take a look at this post. -> link

    How to create the missing EFI System partition.

    The EFI System partition is required to boot the computer, when you are using the GPT partition style. The UEFI firmware scan your computer's hard disks for existence of the EFI System partition, then run \efi\boot\bootx64.efi file in the EFI System partition. This partion has to be formatted with FAT32 file system.

    - For Advanced Format Generation One (4-KB-per-sector) drives, the minimum size of this partition is 260 MB.
    - For earlier 512-byte-per-sector drives, the minimum size of this partition is 100 MB.

    Click image for larger version

    CONTENTS:

    - Option One: How to create the missing EFI System partition, if you still have the unallocated space available for the EFI System partition and no other unallocated space on the drive.
    - Option Two: How to create the missing EFI System partition, if you have the unallocated space available for the EFI System partition.
    - Option Three: How to create the missing EFI System partition, if you do NOT have the unallocated space available for the EFI System partition.

    > OPTION ONE <

    How to create the missing EFI System partition, if you still have the unallocated space available for the EFI System partition and no other unallocated space on the drive.

    - Boot the computer using the Windows 7/8/8.1 installation media.
    - On the first screen, press SHIFT+F10 to bring up the command prompt.
    - Run the following commands at the command prompt.

    diskpart
    list disk
    select disk # Note: Select the disk where you deleted the EFI System partition.
    list partition
    create partition efi
    format quick fs=fat32
    list partition
    list volume Note: Note the volume letter where the Windows OS is installed.
    exit

    bcdboot X:\windows Note: Replace "X" with the volume letter of the Windows OS partition.

    BCDBoot copies the boot files from the Windows partition to the EFI System partition and creates the BCD store in the same partition.

    - Remove the Windows installation media and restart the computer.

    Click image for larger version

    Click image for larger version

    > OPTION TWO <

    How to create the missing EFI System partition, if you have the unallocated space available for the EFI System partition.

    - Boot the computer using the Windows 7/8/8.1 installation media.
    - On the first screen, press SHIFT+F10 to bring up the command prompt.
    - Run the following commands at the command prompt.

    diskpart
    list disk
    select disk # Note: Select the disk where you want to add the EFI System partition.
    list partition
    create partition efi size=260
    format quick fs=fat32
    list partition
    list volume Note: Note the volume letter where the Windows OS is installed.
    exit

    bcdboot X:\windows Note: Replace "X" with the volume letter of the Windows OS partition.

    BCDBoot copies the boot files from the Windows partition to the EFI System partition and creates the BCD store in the same partition.

    - Remove the Windows installation media and restart the computer.

    Click image for larger version

    Click image for larger version

    > OPTION THREE <

    How to create the missing EFI System partition, if you do NOT have the unallocated space available for the EFI System partition.

    - Boot the computer using the Windows 7/8/8.1 installation media.
    - On the first screen, press SHIFT+F10 to bring up the command prompt.
    - Run the following commands at the command prompt.

    diskpart
    list disk
    select disk # Note: Select the disk where you want to add the EFI System partition.
    list partition
    select partition # Note: Select the Windows OS partition or your data partition.
    shrink desired=260
    create partition efi size=260
    format quick fs=fat32
    list partition
    list volume Note: Note the volume letter where the Windows OS is installed.
    exit

    bcdboot X:\windows Note: Replace "X" with the volume letter of the Windows OS partition.

    BCDBoot copies the boot files from the Windows partition to the EFI System partition and creates the BCD store in the same partition.

    - Remove the Windows installation media and restart the computer.

    Click image for larger version

    Click image for larger version

    Other instructions.

    - Here is info about UEFI Boot Mode (installing using the GPT partition style) and Legacy BIOS Boot Mode (installing using the MBR partition style). -> link
    - How to download and clean install Windows 8.1 if you have an OEM computer with UEFI firmware (BIOS) embedded Windows 8/8.1 product key. -> link

    How to delete the EFI System partition.

    - Windows 7/8/8.1 does not start, if you delete the EFI System partition.
    - If you want to delete the EFI System partition, you must use the delete partition override command.

    - Boot the computer using the Windows 7/8/8.1 installation media.
    - On the first screen, press SHIFT+F10 to bring up command prompt.

    diskpart
    list disk
    select disk #
    list partition
    select partition # Note: Make sure to select the EFI System partition.
    delete partition override
    Last edited by genet; 27 Oct 2015 at 23:36.
      My System SpecsSystem Spec

  5. #5


    Posts : 8
    Win 8


    Quote Originally Posted by genet View Post
    - Boot the computer using the Windows 7/8/8.1 installation media.
    - On the language screen, press SHIFT+F10 to bring up command prompt.
    - Run the following commands at the command prompt.

    bootrec /fixboot

    diskpart
    list disk
    select disk 0
    list partition
    select partition # Note: Select the partition where the Windows OS is installed.
    shrink desired=260 minimum=260
    create partition efi
    list partition
    select partition # Note: Select the System 260 MB (or 261 MB) partition.
    format fs=fat32 label="System"
    list volume Note: Note the drive letter where the Windows OS is installed.
    exit

    bcdboot X:\windows Note: Replace "X" with the drive letter of the Windows OS partition.

    Attachment 49466

    Attachment 49467
    Many thanks for your answer! I'll try to get this Windows back to life first.
    I tried the above, but I can't shrink the volume with Windows: Error message "You may not shrink OEM, ESP or recovery partition, or, offline volumes"
    The disk incidentally contains two partitions: Partition 1 (128MB, Reserved; can't assign a drive letter to this, so I don't know what's on it), Partition 2 (Windows, System).
    Any other ideas?
      My System SpecsSystem Spec

  6. #6


    Quote Originally Posted by midou35000 View Post
    You can download EaseUS Partition recovery from:Download Free Partition Recovery Software - EaseUS Partition Recovery install it and run it
    Hope that helps.
    Very good program indeed !

      My System SpecsSystem Spec

  7. #7


    Posts : 8
    Win 8


    Quote Originally Posted by vrosa View Post
    Quote Originally Posted by midou35000 View Post
    You can download EaseUS Partition recovery from:Download Free Partition Recovery Software - EaseUS Partition Recovery install it and run it
    Hope that helps.
    Very good program indeed !



    I can't install any recovery programs as my Windows isn't booting!!
      My System SpecsSystem Spec

  8. #8


    Posts : 1,121
    Windows 8.1 x64


    You don't have to install, just get a version which will allow for booting to the media. Partition Wizard will do this. You might be able to take a picture of your drives configurations (graphical presentation of partitions) with a camera if the software you use does not have the option of copying a screen shot to a flash drive.

    I will say again, do not use EaseUS partition management software for a UEFI install. It has and probably still does, mess with the Recovery partitions and makes that option unusable.
      My System SpecsSystem Spec

  9. #9


    Posts : 879
    Windows 10


    Quote Originally Posted by naujoks View Post
    I tried the above, but I can't shrink the volume with Windows: Error message "You may not shrink OEM, ESP or recovery partition, or, offline volumes"
    The disk incidentally contains two partitions: Partition 1 (128MB, Reserved; can't assign a drive letter to this, so I don't know what's on it), Partition 2 (Windows, System).
    Click image for larger version

    You must select the partition where the Windows OS is installed.

    diskpart
    list disk
    select disk # Note: Select the disk where the Windows OS is installed.
    list partition
    select partition # Note: Select the partition where the Windows OS is installed.
      My System SpecsSystem Spec

  10. #10


    Posts : 8
    Win 8


    Quote Originally Posted by genet View Post
    Quote Originally Posted by naujoks View Post
    I tried the above, but I can't shrink the volume with Windows: Error message "You may not shrink OEM, ESP or recovery partition, or, offline volumes"
    The disk incidentally contains two partitions: Partition 1 (128MB, Reserved; can't assign a drive letter to this, so I don't know what's on it), Partition 2 (Windows, System).
    Click image for larger version

    You must select the partition where the Windows OS is installed.

    diskpart
    list disk
    select disk # Note: Select the disk where the Windows OS is installed.
    list partition
    select partition # Note: Select the partition where the Windows OS is installed.
    That's what I'm doing. In my frustration I tried to re-install Winodws on the same partition where the old installation is, but that isn't working either: "The selected disk is of the GPT partition style. Windows cannot be installed to this hard disk space. The partition is an EFI system partition (ESP)."
    Unbelievably, yes, it seems to think that the main space where my Windows resides is an EFI partition! That's also the reason why I can't shrink it.
      My System SpecsSystem Spec

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