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Windows 8 can't start due to missing EFI partition


naujoks

New Member
Posts
8
#1
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?
 

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midou35000

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#2

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Saltgrass

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#3
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.
 

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System One

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genet

New Member
Guru
Posts
879
#4
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.

Windows 8.1 - list partition.png

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.

Create partition efi 1.png

Create partition efi 2.png

> 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.

EFI System partition 1.png

EFI System partition 2.png

> 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.

Create EFI System partition 1.png

Create EFI System partition 2.png

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:

My Computer

System One

  • OS
    Windows 10
    Computer type
    Laptop
    System Manufacturer/Model Number
    Lenovo G580
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    Intel Core i5-3230M
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    Intel HD Graphics 4000
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    Windows Defender, standard user account
    Other Info
    UEFI firmware (BIOS) embedded Windows 8 product key.

naujoks

New Member
Posts
8
#5
- 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.

View attachment 49466

View 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 Computer

System One

  • OS
    Win 8

vrosa

Tech Addict
VIP Member
Pro User
#6

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Saltgrass

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#8
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 Computer

System One

  • OS
    Windows 8.1 x64
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    Home Grown
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    i7 3770K
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genet

New Member
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Posts
879
#9
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).
Error message.png

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 Computer

System One

  • OS
    Windows 10
    Computer type
    Laptop
    System Manufacturer/Model Number
    Lenovo G580
    CPU
    Intel Core i5-3230M
    Memory
    8 GB
    Graphics Card(s)
    Intel HD Graphics 4000
    Browser
    Microsoft Edge
    Antivirus
    Windows Defender, standard user account
    Other Info
    UEFI firmware (BIOS) embedded Windows 8 product key.

naujoks

New Member
Posts
8
#10
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).
View attachment 49476

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 Computer

System One

  • OS
    Win 8

genet

New Member
Guru
Posts
879
#11
In my frustration I tried to re-install Windows 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)."
Error message when you boot in Legacy BIOS Boot Mode:

Error message 2.png

You need to select to boot from the UEFI type (marked UEFI in the boot menu) if you want to install Windows 8 64-bit in UEFI boot mode.

Here is info about Legacy BIOS Boot Mode (installing using the MBR partition style) and UEFI Boot Mode (installing using the GPT partition style): LINK

edit:

Error message when you boot in UEFI Boot Mode:

Error message 3.png
 
Last edited:

My Computer

System One

  • OS
    Windows 10
    Computer type
    Laptop
    System Manufacturer/Model Number
    Lenovo G580
    CPU
    Intel Core i5-3230M
    Memory
    8 GB
    Graphics Card(s)
    Intel HD Graphics 4000
    Browser
    Microsoft Edge
    Antivirus
    Windows Defender, standard user account
    Other Info
    UEFI firmware (BIOS) embedded Windows 8 product key.

naujoks

New Member
Posts
8
#12
In my frustration I tried to re-install Windows 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)."
Error message when you boot in Legacy BIOS Boot Mode:

View attachment 49481

You need to select to boot from the UEFI type (marked UEFI in the boot menu) if you want to install Windows 8 64-bit in UEFI boot mode.

Here is info about Legacy BIOS Boot Mode (installing using the MBR partition style) and UEFI Boot Mode (installing using the GPT partition style): LINK
I am trying and want to install in UEFI Boot Mode and have selected my install DVD accordingly. That's not it either.
 

My Computer

System One

  • OS
    Win 8

genet

New Member
Guru
Posts
879
#13
Quote from this post:

Normally, you should be able to delete all the partitions on the Where do you want to install Windows? screen.

Note: But if you cannot delete all the partitions on the Where do you want to install Windows? screen.

- Boot the computer using the Windows 7/8/10 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 (this will give you a listing of the disks on your system)
select disk # (select the disk you want to clean, for example select disk 0)
clean (running the clean command will delete all partitions on the disk)
exit

Even if you are going to use the GPT (GUID Partition Table), you do not need to run the convert gpt command, since you are not creating the partitions at a command prompt.

- Close the command prompt window and continue your Windows installation as usual.

Diskpart.png
 
Last edited:

My Computer

System One

  • OS
    Windows 10
    Computer type
    Laptop
    System Manufacturer/Model Number
    Lenovo G580
    CPU
    Intel Core i5-3230M
    Memory
    8 GB
    Graphics Card(s)
    Intel HD Graphics 4000
    Browser
    Microsoft Edge
    Antivirus
    Windows Defender, standard user account
    Other Info
    UEFI firmware (BIOS) embedded Windows 8 product key.

naujoks

New Member
Posts
8
#14
I ended up having to use the command prompt on the Windows install disk to copy things manually from my C: drive to an external HDD. Very boring and laborious.
I then finally managed to install Windows after formatting the whole drive. It was the last thing I wanted to do, but at least now all the relevant partitions are on that drive, so that's good.
Still find it hard to believe that despite the drive containing a working Windows partition I was unable to get it to boot. This definitely would not have happened under Windows 7!
Thanks for all your help though!
 

My Computer

System One

  • OS
    Win 8
#15
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?
Losing stuff is hard.
Save what you can to usb.

I suggest restoring to factory specs & starting from scratch.

Then getting Macrium Reflect to image all your local drives on usb. {32 or 64 GB size should do with maximum compression.}

Macrium has been a god-send to me. :)
 

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System One

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    Windows 8.1.1 Pro with Media Center
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    System Manufacturer/Model Number
    Gateway
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    AMD K140 Cores 2 Threads 2 Name AMD K140 Package Socket FT1 BGA Technology 40nm
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    Manufacturer Gateway Model SX2110G (P0)
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    Type DDR3 Size 8192 MBytes DRAM Frequency 532.3 MHz
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    ATI AMD Radeon HD 7310 Graphics
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    AMD High Definition Audio Device Realtek High Definition Audio USB Audio Device
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    Name 1950W on AMD Radeon HD 7310 Graphics Current Resolution 1366x768 pixels Work Resolution 1366x76
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    Current Resolution 1366x768 pixels Work Resolution 1366x768 pixels
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    AMD K140
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    Technology 40nm
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    Extended Family 14
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    Revision ON-C0
    Instruction
    Browser
    Opera 24.0
    Antivirus
    Avast Internet Security

kevbeek

New Member
Posts
1
#17
Kudos to you. My EFI partition for windows 10 was on a different drive than the OS. When I flashed a Linux OS on the drive with the EFI partition, the boot command for Windows was erased. Option 3 fixed my problem. Thanks!
 

My Computer

System One

  • OS
    Windows 10

ccar12345

New Member
Posts
1
#18
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.

View attachment 63079

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.

View attachment 63090

View attachment 63091

> 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.

View attachment 63086

View attachment 63087

> 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.

View attachment 63093

View attachment 63094

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

Amazing!!!, 3 years later this post save my life and work, ****! thank you very much for that instructions !!!!
 

My Computer

System One

  • OS
    win10