Windows 10: Windows won't boot in UEFI mode, deleted EFI partition.

Discus and support Windows won't boot in UEFI mode, deleted EFI partition. in Windows 10 Installation and Upgrade to solve the problem; Okay, so the other week i received a new Clevo P650SE laptop. The laptop only had a 500GB 7200RPM HDD with Windows 10 to begin with, so yesterday i... Discussion in 'Windows 10 Installation and Upgrade' started by OnePlus, Aug 24, 2015.

  1. OnePlus Win User

    Windows won't boot in UEFI mode, deleted EFI partition.


    Okay, so the other week i received a new Clevo P650SE laptop. The laptop only had a 500GB 7200RPM HDD with Windows 10 to begin with, so yesterday i added my Samsung 840 EVO SSD. As i wanted this to now be the primary drive, i made another new installation of Windows onto here. After doing this, the system now displayed a boot selection at startup with the choice between the new Windows 10 installation on my SSD or the old one on the HDD.

    As i no longer wanted to use the HDD for running Windows, i decided it would be best to delete Windows from this drive. So i booted onto an Ubuntu USB and wiped the entire drive of it's data in GParted, which included three different partitions. This seemed perfectly fine to me at the time, because i had a the new installation from the SSD showing up in the boot manager.

    However, when i rebooted the machine and attempted to boot into the new installation on the SSD, it gives me this message:

    "The boot configuration data from your PC is missing or contains errors.
    File: /EFI/Microsoft/Boot/BC Error code: 0xc000000f"


    I have tried everything to recover the system but nothing has worked. Startup repair from my Windows USB doesn't do anything, the system reset wouldn't operate because it stated that the partition was locked.

    Nothing with the Command Prompt is helping me either, i have done 'bootrec /fixmbr', 'bootrec /fixboot' and 'bootrec /rebuildbcd', but the last command returns the following error:

    "The requested system drive cannot be found."


    I also did 'bcdboot C:/Windows' but that also refused to work. I assumed the reason for this might be because the drive didn't have a letter, but when i attempted to add a letter is says:

    "The specified drive letter is not free to be assigned."


    Both drives in my laptop have now been completely wiped and converted to MBR, but even with the two drives empty the original message still appears when booting my Windows USB in UEFI.

    I'm kind of scared because i have only had this laptop a couple of weeks and it's already completely messed up. I can boot the Windows USB in Legacy and install Windows as normal, but of course i'm looking to have it back on UEFI as it was before.

    Any help would be massively appreciated as i'm rather stressed about this at the moment.


    :)
     
    OnePlus, Aug 24, 2015
    #1

  2. Grub 2 does not detect windows partition by osprober

    To boot Windows on a GPT disk, the PC must be in UEFI BIOS mode.

    You can write the Windows boot files to the EFI partition, or recreate it, from a Command Prompt. The best way is to boot with Windows install media. Once it loads to Windows setup, use SHIFT-F10 to get a Command Prompt.

    You said that you deleted the EFI FAT32 partition. That was probably the Windows System partition. Legacy BIOS on an MBR disk, uses a combined System/Recovery partition by default, but UEFI put them in separate partitions. Windows 10 needs a 100MB EFI partition,
    of which usually less than 30MB is used for System files. The EFI partition can be anywhere.

    At the Command Prompt, run diskpart to recreate the EFI/System partition.

    Assuming that there is still 100MB of unallocated space where the EFI partition was:

    diskpart

    create partition EFI

    format quick fs=FAT32

    assign letter=S

    exit

    Then run bootsect:

    bootsect /nt60 S: /force

    Bcdboot will create the Windows System files on S: If Windows does not show up on C:, use whatever letter it is currently on in the command below:

    bcdboot C:\Windows /s S: /f UEFI

    I don't know the details on how Fedora Linux boots in UEFI mode, assuming that it will. I have read that some rename the grub file to match the Windows System EFI boot file name when dual-booting. I suspect that there are various approaches to getting it
    to work.
     
    Don Cuthbert, Aug 24, 2015
    #2
  3. Always booting from the wrong drive

    The presence of the EFI System and MSR reserved partitions on the old install means it's a UEFI install to GPT disk. When you installed to the new disk it used the existing EFI System partition to Dual Boot so that when it was detached the new install cannot
    boot. Had you not wanted the old install you should have unplugged it's drive during install. If you did anything else like installed the new Windows in Compatibility mode please advise.

    Now if this were the Legacy BIOS with an MBR disk we could simply mark the new install's partition Active and run a few Startup Repairs or Rebuild the BCD to get it booting. But for UEFI there must be at least the EFI System partition to boot it. You
    can create one by shrinking the Windows partition from the left by a minimum 500mb I'd recommend.

    Then try either a bootable partition Manager or Diskpart from the Command Prompt of the booted Windows media to create the EFI System partition:

    Create EFI System Partition in Easy Steps to Make Windows Bootable Again

    Restore/Repair Deleted EFI Boot Partition in Windows 10/8/7 – EaseUS

    If you can create it but it still won't boot then try a Startup Repair, or
    Rebuild the BCD in Windows [10 to 20 Minutes]
    as a last resort to export
    and rebuild which often works. **Note that the commands given to copy boot files must reference the EFI System partition and not Windows partition.

    When doing these operations unplug all other physical drives. Plug the target Windows drive into SATA 1 which should be DISK 0.
     
    Greg Carmack - Windows MVP, Aug 24, 2015
    #3
  4. Rudy Mas Win User

    Windows won't boot in UEFI mode, deleted EFI partition.

    You have to make a Windows USB that has UEFI support on it.

    You can best use RUFUS for this and use "partition scheme for UEFI".

    This should work.
     
    Rudy Mas, Aug 24, 2015
    #4
  5. OnePlus Win User
    Yeah, i have already done that. Unfortunately the problem seems to be with the EFI partition on the original hard drive which i deleted by accident.
     
    OnePlus, Aug 24, 2015
    #5
  6. Rudy Mas Win User
    Well, this worked for me.

    I had to make this kind of USB on my HP ProBook, else I couldn't set me BIOS to SecureBoot / UEFI Native (Without CSM).

    Normally, it doesn't matter what is on de harddrives, because it finds all the boot up information on the USB stick. The harddrives in the system doesn't even have to have a partition on it for this.

    How did you create the USB stick? The only program that worked for me was RUFUS. The tool to make bootable USB's from a downloaded Windows 10 from Microsoft didn't work for me
     
    Rudy Mas, Aug 24, 2015
    #6
  7. genet Win User
    Quote from this post: UEFI Boot Mode (installing using the GPT partition style) and Legacy BIOS Boot Mode (installing using the MBR partition style).

     
    genet, Aug 24, 2015
    #7
  8. OnePlus Win User

    Windows won't boot in UEFI mode, deleted EFI partition.

    I see what you mean, but i am confident there is nothing wrong with the USB because i have used it on this laptop previously with out issue. The bootable USB was created using Rufus, the same tool that you used. When i created the USB, i selected the option for a both UEFI and MBR compatibility. This is what i'm struggling to understand, i don't see why the drives should make any difference under these circumstances.
     
    OnePlus, Aug 24, 2015
    #8
  9. Rudy Mas Win User
    That doesn't work. You need to choose "GPT partition scheme for UEFI" and formatting in FAT32.

    The one you made, will only boot in Legacy mode.
     
    Rudy Mas, Aug 24, 2015
    #9
  10. OnePlus Win User
    In my original post i didn't state this because i wanted to keep things simple, but the laptop actually came with Windows 8 and i wiped the drive and upgraded straight to Windows 10 using this USB in UEFI mode. I can try using the other mode but i don't think it would make any difference.
     
    OnePlus, Aug 24, 2015
    #10
  11. Rudy Mas Win User
    It will, trust me. *Wink

    As I understood, your system came with Windows 10 installed, so it probably had an EFI partition on it. This was used by your USB stick when it booted. Now that it is gone, the USB stick can't find the information anymore it needs to boot. That's why you have to create the USB stick in a way that all the necessary information is on it, so it doesn't need anything from other sources.
     
    Rudy Mas, Aug 24, 2015
    #11
  12. OnePlus Win User
    Hmm, okay i do understand what you mean for sure now. You raise an interesting point and at the moment i am currently making the new USB with only the UEFI option enabled. I'm still a bit nervous about this though, because as i stated in the previous message the laptop actually came with Windows 8 installed and i wiped the hard drive and upgraded to Windows 10 afterwards. So at this point, i imagine the hard drive would possibly have been in the same condition as it is now, without the EFI partition, but i can't quite remember how i wiped it that time.

    I'll let you know what happens in a short while. *Smile
     
    OnePlus, Aug 24, 2015
    #12
  13. NavyLCDR New Member

    Windows won't boot in UEFI mode, deleted EFI partition.

    Have you ever actually upgraded the original Windows 8 to Windows 10 from inside Windows 8? If you did not, was your Windows 10 activated? Are you trying to use the free Windows 10 upgrade? You might be trying to do all this only to end up with a Windows 10 that won't activate.
     
    NavyLCDR, Aug 24, 2015
    #13
  14. Kyhi Win User
    the issue you are having - is because when you did the New installation of windows 10 on your New (second) SDD

    The new installation place the boot record on the old EFI Partition (which has been deleted)

    You must shrink one of the partitions on the New SSD by 228MB and recreate an EFI partition

    and will have to also have to recreate the the MS Reserved partition
    Then write the boot files to the new EFI partition

    Actually you are way better off, just unplugging the OLD HDD and doing a clean Installaion of windows 10 on the New SDD

    then plugin the Old HDD for use as a second DATA drive
     
  15. OnePlus Win User
    Yeah, this is what i tried to do earlier but didn't have much success. The problem i had with this was, i needed the SSD to be GPT for UEFI to work, but in order to copy the boot files an installation of Windows already had to be installed.

    I installed Windows onto my SSD and attempted to copy the boot files to an EFI partition that i had created on the normal hard drive but this didn't seem to work. Maybe if i do it the other way around like you say, then it would be okay.

    It's difficult though because i have little experience with using DiskPart to create these setups. Last time i followed this tutorial, but i found it a bit difficult to adapt to my current situation. I'm well outside of my comfort zone with this stuff.

    Windows 8 can't start due to missing EFI partition.
     
    OnePlus, Aug 24, 2015
    #15
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Windows won't boot in UEFI mode, deleted EFI partition.

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