I had to resize my EFI partition and formated it, it deleted the Microsoft folder in it and I am no longer able to boot on windows 10. I'd like to restore the boot ability on windows 10.

I went into the recovery mode command line in the windows 10 disk and typed bootrec /rebuildbcd it found my windows 10 install and said the reconstruction was successful, however I can't boot on the entry it creates in the efi boot menu (nothing happens when I select it). Any idea on how to repair windows 10 boot ?

4 Answers 4


You CANNOT fix a EFI boot with /fixmbr. That will screw up your GPT disk and return it to MBR two different beasts.

To fix EFI boot load your Windows USB using the function key to get to setup menu click allow EFI USB.

A box comes up wanting to upgrade click NO.

The Windows install window then comes up, click NEXT Repair Computer > Troubleshoot... > Advanced > Command Prompt

At the command prompt:

list disk  /* rem with a USB and HDD you will only have two selections
sel disk 0 
list vol
sel vol    /* rem look for SYSTEM FAT32 hidden ~100 MB mine was sel vol 3 yours maybe different
format fs=fat32 quick label=(optional)
list vol   /*rem look for and remember which Volume Windows is C or D ?
/* then...
bcdboot C:\Windows

Now here if it hangs up after a minute hit CTRL + c. (I don't know why it does this sometimes but you will get a message boot files successfully created and it will boot just fine into Windows.)


Click on Turn Off Computer, Remove USB and restart.

  • In my situation, I had another machine that started bluescreening on boot. I put the main disk from this system in my backup machine. This disk was higher in the boot order and booted the first time the system started. I didn't change the default, but selected the correct disk from a list to boot the OS disk for the backup system. Big mistake. The machine faithfully hibernated at night. I tapped the power button to start it up and the other machine's OS disk ran, did a recovery and seemed to eat my correct-disk's EFI partition, rendering it non-booting. This fixed me. Thanks so much! Apr 1, 2020 at 18:22

(This is an update on knotheu's excellent answer.)

An EFI boot must be repaired with the proper tool. (The mostly-legacy MBR-BIOS disk setups would use the fixmbr tool.)

To fix an EFI boot either boot into the Windows Recovery Environment by:

  • using the UEFI-defined function key too boot the Win RE partition (if your computer has one)
  • using a USB recovery drive to boot Win RE (hopefully the reader had the foreknowledge to create this) [additionally an UEFI setting may have to be edited to allow a USB device boot priority]

When Win RE has booted, get to the command prompt by something akin to: Troubleshoot…Advanced OptionsCommand Prompt. From there:

diskpart               # disk-partition editor/formatter…
list disk
select disk [0-9]      # the EFI System partition is usually on disk 0
list partition
sel partition [0-9]    # the EFI _System_ partition is usually the first [1]
detail partition       # details if formatted, healthy, _System_ partition
  ! the next command nullifies any current data on the partition !
  I had to do this because my partition showed RAW, `chkdsk` lacked success,
  zero files were on it; though this method did work for me to restore
  Windows booting, I would recommend try to fix the boot partition first.
format fs=fat32 quick label=System
list vol               # disk label "Windows" to determine disk letter

With the System partition formatted and the knowledge of the Windows directory disk letter, the next step is to copy the the boot files to the EFI System partition and I believe the NVRAM gets updated:

mountvol S: /S                       # the System partition mount to S:
bcdboot c:\windows /s s: /f UEFI /v  # `bcdboot c:\windows` may be enough
                                       /s for mountpoint, /f for firmwaretype
                                       /v for verbose
exit                                 # then rm USB is used, reboot
  • One thing you forgot was to label the partition like so: assign letter=S
    – Dr. Tyrell
    Dec 10, 2017 at 19:47
  • Thanks bcdboot needed drive letter of EFI in order to work Jul 16, 2020 at 23:12

Step 1: On start-up insert a pen drive where WINDOWS 10 is loaded as bootable

Step 2: Now select Language and click NEXT

Step 3: Now click Repair your computer

Step 4: Click Advanced -> Command Prompt

Step 5: Type in this command

bcdboot c:\Windows /l en-us /s c: /f ALL

The line above solutions all.

Step 6: Type exit, shot down sytem, remove pendrive and restart your system to resolve this error.

It was very helpfull and simple solution for me on error "Bootmgr missing press crtl+alt+supr" on a Windows 10 that could not fix with Bootrec command.


Did you do the rebuildbcd in the following order? (press enter after each one)


if the bootrec /rebuildbcd results in

Successfully scanned Windows installations. Total identified Windows installations: 1

[1] D:\Windows Add installation to boot list? Yes/No/All:

And it's not working after, try the following:

  • chkdsk /r

After the check disk is completed, you may try booting the computer and check if that resolves the issue. If not,

  • SFC /SCANNOW command to rebuild or recover the corrupted system files on the computer.

Reboot & Check

  • 2
    FIXMBR is likely to screw everything on GPT disks.
    – mirh
    Mar 19, 2017 at 14:48

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