Lost UEFI when reinstalling Windows 10

  1. Posts : 2
    Windows 10

    Lost UEFI when reinstalling Windows 10

    I have a laptop that had Windows 7, but was upgraded to Windows 10 with the free upgrade option.

    Everything was getting really slow and full of unneeded software, so I decided to do a clean reinstall Windows 10. I downloaded a copy of Windows 10 to a USB drive as directed here: Download Windows 10

    But I couldn't boot from the USB drive unless I turned off UEFI and the "secure mode" settings, and instead used the legacy BIOS boot settings without "secure mode".

    I then deleted all partitions and reinstalled Windows 10 on the new blank memory.

    Eveyrthing went fine, but when I try to change the settings back from legacy BIOS to UEFI it says there is nothing to boot. It only works when in legacy BIOS mode.

    I want my installation to be very secure from hacking, so how can I reinstall the UEFI settings so I can turn the secure mode back on?

    I have no idea how all this stuff works - but from Googling I think I messed up by deleteing the partition that held the UEFI setting. Any way I can reconfigure that and fix what I did?
      My Computer

  2. WOT
    Posts : 471
    Win 10 Pro 15063.332 (ex-Insider)

    Your installation media apparently was not UEFI bootable.

    Follow these instructions to create a bootable Windows 10 USB drive for Legacy BIOS and/or UEFI:
    Create Bootable USB Flash Drive to Install Windows 10

    2. Set your BIOS to UEFI defaults then disable Secure Boot and Fast Boot (if enabled):
    (You can turn those 2 options back on after the installation is completed)

    3. Select the UEFI option when booting from the new media and away you go!

    Good luck,

      My Computers

  3. Posts : 1,079
    10 + Linux

    I do believe you made the error of selecting the first one (BIOS or UEFI). It won't boot in UEFI, <<no boot device was found>> will be shown. You will get the same result with Ubuntu or Opensuse. Second and third option works.
    Attached Thumbnails Attached Thumbnails Lost UEFI when reinstalling Windows 10-uefi.png  
      My Computer

  4. Posts : 2
    Windows 10
    Thread Starter

    Got it working thanks guys!

    I used the same boot USB I had before, but this time I selected UEFI for installation in the boot menu. I must have misse that somehow the first time around.
      My Computer

  5. WOT
    Posts : 471
    Win 10 Pro 15063.332 (ex-Insider)

    That's great news! Glad you got it sorted and thanks for reporting you fix too!

    Please mark this thread as solved.


      My Computers


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