Hi.

You can create a lost/deleted EFI partition by CMD.

1) Create an installation media
2) Boot PC with an installation media
3) Press SHFIT + 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
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)

(bcdboot m:\windows command will copy the boot files from Windows partition to the EFI system partition and create BCD store in the partition)

Next remove installation drive and restart your computer

Let me know if you have any questions

So I booted using the thumb drive and chose the Windows 10 repair option but it did not help.

Which repair options were tried and what were the results for each?

Use a camera or smartphone camera to take pictures and post images of these commands and results.

Post the images into the thread using share links:  one drive, drop box, or google drive

Open command prompt and type or copy and paste:

bcdedit /enum

bcdedit | find "osdevice"

diskpart

list disk

list volume

select disk 0

detail disk

list partition

select partition 1

detail partition

select partition 2

detail partition

select partition 3

detail partition

select partition 4

detail partition

select partition 5

detail partition

(If there are any additional partitions on disk 0 then continue in the same fashion)

select disk 1

detail disk

list partition

select partition 1

detail partition

select partition 2

detail partition

select partition 3

detail partition

select partition 4

detail partition

select partition 5

detail partition 

(If there are any additional partitions on disk 0 then continue in the same fashion)

select disk 2

detail disk 

list partition

exit

Thanks Mark. When I try to create an efi partition on my disk 0, it complains that there is not enough usable space for this operation. Disk 0 shows 4 partitions:

Partition 1 - Recovery - 450 MB

Partition 2 - System - 100 MB

Partition 3 - Reserved - 16 MB

Partition 4 - Primary - 930 GB

Do I need to delete one of the partitions?

Hi,

You can delete a less important partition created already and merge the space together to create a new partition with a proper drive letter.

Deleting the partitions created by the OEM is often not possible due to the way the OEMs configure the partitions. Therefore the option then is to extend the operating system partition back to the original size to regain use of the unallocated space.

Be sure that you will not delete drive with your data!

The partitions you are showing are normal Win 10 partitions.  The System partition is where the boot files should be.

Have you checked your Bios to make sure the Windows Boot Manager is listed first in the boot options?

You say you deleted the partition, but it is still there.  Did you wipe it as opposed to removing it?