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?

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.

Originally Posted by genet

- 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?

Originally Posted by vrosa

Originally Posted by midou35000

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!!

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.

Originally Posted by naujoks

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).

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.

Originally Posted by genet

Originally Posted by naujoks

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).

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.