none
changing bios from legacy to UEFI hybrid with CSM or to UEFI native without CSM for upgrades

    Question

  • One of my computers was upgraded from windows 7 professional to windows 10 version 1511 with the bios still in Legacy. It was then upgraded to version 1607.

    Now there is another version upgrade to 1703 and I would appreciate information on how to change the bios to UEFI native without CSM.

    There are no plans to return to windows 7.

    Can the bios setting just be changed at this point in time from Legacy to UEFI native without CSM?  Or will there be problems?  Does it require a clean install before changing the bios settings?

    If the bios setting was changed to UEFI hybrid with CSM before the upgrade from windows 7 professional to windows 10 version 1511 would that have altered what can be done with the next upgrade?

    Tuesday, April 11, 2017 1:53 PM

Answers

  • Hi questionsformicrosoftproducts,

    For Windows 10 1703 version, I have a good news for you. We could converts a disk from Master Boot Record (MBR) to GUID Partition Table (GPT) partition style without modifying or deleting data on the disk.

    Upgrade to Windows 10 1703, convert the disk from MBR to GPT with the MBR2GPT.EXE tool then modify the BIOS configuration.

    Here is a video for reference:
    https://techcommunity.microsoft.com/t5/Windows-10/Shifting-from-BIOS-to-UEFI-with-the-Windows-10-Creators-Update/m-p/61169

    Here is a link for reference of the MBR2GPT.EXE tool
    MBR2GPT.EXE
    https://technet.microsoft.com/en-us/itpro/windows/deploy/mbr-to-gpt

    Best regards

    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Wednesday, April 12, 2017 8:04 AM
    Moderator

All replies

  • From what I have experienced, the OS has to be re-installed to get the benefit of UEFI boot. When the OS is being installed with UEFI enabled, the EFI partitioning (GUID) gets created, which the firmware uses to find the boot sector.

    Note: You have to be using 64-bit Windows OS as the firmware is most likely setup for 64-bit.

    If you try to change the BIOS now with the OS might not boot.

    Windows 7 never really supported UEFI boot so it is not worth the effort to Windows 7 for a re-install.


    Sean Liming - Book Author: Starter Guide Windows 10 IoT Enterprise - www.annabooks.com / www.seanliming.com

    Tuesday, April 11, 2017 2:23 PM
  • Hi questionsformicrosoftproducts,

    For Windows 10 1703 version, I have a good news for you. We could converts a disk from Master Boot Record (MBR) to GUID Partition Table (GPT) partition style without modifying or deleting data on the disk.

    Upgrade to Windows 10 1703, convert the disk from MBR to GPT with the MBR2GPT.EXE tool then modify the BIOS configuration.

    Here is a video for reference:
    https://techcommunity.microsoft.com/t5/Windows-10/Shifting-from-BIOS-to-UEFI-with-the-Windows-10-Creators-Update/m-p/61169

    Here is a link for reference of the MBR2GPT.EXE tool
    MBR2GPT.EXE
    https://technet.microsoft.com/en-us/itpro/windows/deploy/mbr-to-gpt

    Best regards

    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Wednesday, April 12, 2017 8:04 AM
    Moderator
  • MeipoXu

    That was an outstanding video.  Thanks.

    I've got a lot to learn before I can do that.  Would need some hand holding on that one.

    Again thanks.

    Wednesday, April 12, 2017 8:22 AM