Recreating a Lost or Removed EFI Windows Boot Partition (Repair Windows Boot)

Wednesday, January 29th, 2020

Recreating a Lost or Removed EFI Windows Boot Partition

In case you remove an SSD with a Windows Boot Partition that boots an installation of Windows, you'll need to recreate the boot system to be able to successfully boot again.  To recreate the boot EFI partition on another drive or partition, perform the following:

1) Create or use an existing Windows installation disc or flash drive (you can use Rufus USB to format a flash drive with a Windows ISO)
2) Boot PC using your Windows installation media (a CD, DVD, flash drive, etc containing Windows installation files)
3) Press SHIFT + F10 on the first screen to bring up Command Prompt
4) Run the following commands and click Enter each time at Command Prompt:

diskpart
list disk
select disk N (N refers to the disk which contains the deleted the EFI System partition)
list partition
create partition efi size=200
format quick fs=fat32
list partition
list volume (find the volume letter which belongs to the installed Windows OS)
exit (exit diskpart)
bcdboot M:\windows (M refers to the volume letter of installed Windows OS)

Add any additional Windows installations by repeating the bcdboot command followed by the installation path for any other Windows installations you want added to the menu.  For example, I added my Windows 7 partition using the below command:

bcdboot P:\windows

You should now be able to boot Windows again without needing the old boot partition or drive.

Instructions were modified from this post.