How to return to UEFI after installing another Windows 10 version in legacy mode

JohnnySR15
JohnnySR15 Member Posts: 13

Tinkerer

edited November 2023 in 2018 Archives
Hello, a few months ago I rebooted my laptop to install the Windows 10 Pro version, but I did it in Legacy mode so now that I try to update the BIOS it does not leave me since it appears to me that my disks must be in GPT and UEFI system, However, I can no longer install the system in UEFI since it does not Boots (Because it comes with the secure Boot activated and blocked). Is there any way to reinstall my windows in UEFI Mode?

Answers

  • JohnnySR15 
    Starting in Windows 10 version 1703 build 15063, you can use the MBR2GPT.EXE command line tool to convert a disk from Master Boot Record (MBR) (used in Legacy BIOS) to GUID Partition Table (GPT) (used in UEFI) without having to clean install Windows 10 or modifying or deleting data on the disk. The tool is designed to be run from a Windows Preinstallation Environment (Windows PE) command prompt, but can also be run from the full Windows 10 operating system (OS).
    Please follow the steps in the below weblink: 
    How to convert an MBR disk to GPT and move from BIOS to UEFI on Windows 10
    Note : This is a third party weblink and  I am not responsible for any data loss that may occur. Please make sure that you have the necessary backup.

    Hit 'Like' if you find the answer helpful!   
    Click on 'Yes' if the comment answers your question!
  • IVAN_PC
    IVAN_PC ACE Posts: 7,568 Pathfinder
    edited September 2018
    Hi.

    You have to do an installation from 0, again and leave bios in their default values, once done the installation in UEFI mode, it would be to modify the bios, that is to say, place the USB first in LEGACY mode so that the different modes can be seen, previously deactivating the secure boot, and before proceeding with the installation and restarting to read the USB, in the window where you put LEGACY, choose UEFI mode.

    Resultado de imaxes para cambiar odo uefi a legacy bios acer

    A greeting.

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  • There is no need to reinstall windows, as, as colleague @Sharanji said, just do the conversion! But it is recommended before you back up!
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  • JohnnySR15
    JohnnySR15 Member Posts: 13

    Tinkerer

    edited September 2018
    Sharanji said:
    JohnnySR15 
    Starting in Windows 10 version 1703 build 15063, you can use the MBR2GPT.EXE command line tool to convert a disk from Master Boot Record (MBR) (used in Legacy BIOS) to GUID Partition Table (GPT) (used in UEFI) without having to clean install Windows 10 or modifying or deleting data on the disk. The tool is designed to be run from a Windows Preinstallation Environment (Windows PE) command prompt, but can also be run from the full Windows 10 operating system (OS).
    Please follow the steps in the below weblink: 
    How to convert an MBR disk to GPT and move from BIOS to UEFI on Windows 10
    Note : This is a third party weblink and  I am not responsible for any data loss that may occur. Please make sure that you have the necessary backup.

    Hit 'Like' if you find the answer helpful!   
    Click on 'Yes' if the comment answers your question!
    I did all the steps but at the moment i tried the command mbr2gpt /validate the process failed i think is because my disk used to be in GPT before i installed the Windows 10 pro in Legacy.
    Btw, i tried the next command mbr2gpt /convert and i got this message " Disk layout validation failed for disk 0" then MBr2GPT: Conversion Failed.

    What can i do in this case?
  • JohnnySR15
    JohnnySR15 Member Posts: 13

    Tinkerer

    There is no need to reinstall windows, as, as colleague @Sharanji said, just do the conversion! But it is recommended before you back up!
    Any idea of how to solve the question above?
  • JohnnySR15
    JohnnySR15 Member Posts: 13

    Tinkerer

    IVAN_PC said:
    Hi.

    You have to do an installation from 0, again and leave bios in their default values, once done the installation in UEFI mode, it would be to modify the bios, that is to say, place the USB first in LEGACY mode so that the different modes can be seen, previously deactivating the secure boot, and before proceeding with the installation and restarting to read the USB, in the window where you put LEGACY, choose UEFI mode.

    Resultado de imaxes para cambiar odo uefi a legacy bios acer

    A greeting.
    I tried this but at the moment that  the system runs the Windows Installation process it appears that the USB didnt have all the drivers... i did it like 20 times. All of the failed.
  • Then you should reinstall windows with a pendrive! Make a backup before reinstalling windows 10!
    Inside the windows 10 installation, you should press shift + f10 and type these commands diskpart, disk list, sel disk x, clean (delete all even if the hd is with two partitions), convert gpt !
    See this manual to help you with how to install windows 10 converted to gpt!
    Oi! Eu não sou sou a cortana! Mas estou aqui para ajudar! Hi! I'm not the cortana! But I'm here to help!
    Se você gostou da minha resposta, marque como solução clicando em sim! If you liked my answer, mark it as a solution by clicking on yes!
    Aceite somente a resposta que ajudou a solucionar o seu problema! Please accept only the response that helped to solve your problem!
    Detection tool click here to find the serial number or partnumber of your model!                                                          
                                                      
                                                     egydiocoelho Trailblazer
     
    ProductKey clique aqui para descobrir o serial do windows! click here to discover the windows serial!
    Para usuários da comunidade inglesa, espanhola, francesa e alemã, usarei o google tradutor! :)
    For users of the English, Spanish, French and German community, I will be using google translator! :)