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Unsupported disk layout for UEFI firmware

Anonymous
2018-03-06T14:50:42+00:00

Hello -

Is there a fix or patch for the error message - "Windows can't be installed because this PC has an unsupported disk layout for UEFI firmware."?  How can I get this taken care of without loosing any of my files?  I see a lot of information on this but am afraid to give some of the reported fixes a try.  Please help. 

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Windows for home | Windows 10 | Install and upgrade

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  1. Anonymous
    2018-03-06T15:01:15+00:00

    Yes. Windows now includes a utility to convert your MBR disk to GPT (which is what UEFI requires) without data loss.

    MBR2GPT.EXE is part of Windows 10 version 1703, which came out in Spring 2017. What version of Windows are you running now? It sounds like you are currently running in Legacy BIOS mode on a PC that is capable of UEFI BIOS mode.

    https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt

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  2. Anonymous
    2018-03-06T17:44:26+00:00

    Yes.  Just download the Media Creation Tool and it will let you download an ISO file for the current version of Windows 10 (version 1709, build 16299.15).  You can also have the Tool directly create a bootable USB stick with version 1709 of Windows on it.  If you already have this ISO file, a utility called Rufus can be used to create a bootable USB stick (8GB minimum size thumb drive required). http://rufus.akeo.ie

    The steps to fix things will be:

    • first create the UEFI-bootable USB stick (it will have a FAT32 format, rather than NTFS) using Rufus or Media Creation Tool
    • Restart the computer and tap F2 to enter BIOS. Switch to UEFI mode.  Leave Secure Boot disabled for now if that is an option.
    • Exit and it will restart with the bootable thumb drive inserted.  This time try tapping F12 which usually gives a boot menu. The USB should show up in the list, if it has been created right for UEFI.
    • Once Windows Setup loads the first screen, use SHIFT-F10 to get a Command Prompt window.
    • Now we can try to run MBR2GPT to convert the disk.
    • First, MBR2GPT can validate that conversion is possible:
      • mbr2gpt /validate
      • assuming it validates OK:
        • mbr2gpt /convert
    • Type exit to return to the Windows setup screen or just close the Command Prompt window.
    • Cancel Windows setup by closing the setup window and let the computer restart to your existing Windows build 10240
    • Once back in Windows, your disk should now be capable of upgrading to build 1709.
    • Version 1803 of Windows 10 will be released this month or in April.  If you want to wait to upgrade directly to that, it would be fine to do that.  Meanwhile, you are now running in UEFI mode.  There is a chance that you might be auto-upgraded by Windows Update to version 1709 anyway, so upgrading now is fine too.
    • To upgrade now, from within Windows run setup.exe from your mounted ISO file or USB stick.  Do not boot from the install media to upgrade.
    • You can also now tap F2 during boot to enter BIOS and enable Secure Boot

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  3. Anonymous
    2018-03-06T17:13:54+00:00

    I will let him tell us the details, but it sounds to me like he is running setup.exe to upgrade Windows 10 from within running Windows.  If he was running Legacy BIOS mode, he could not boot UEFI media and if he has switched to UEFI BIOS mode, his existing Windows 10 would not boot.  If he is booting Windows install media and wants to upgrade, setup will say to run it from within Windows instead.  I think that sometimes Windows setup detects a UEFI-capable PC, running in Legacy BIOS mode, and tries to force a switch to UEFI mode.

    In any event, he can run MBR2GPT to convert the drive without formatting or losing data.  If he does not yet have version 1703 or greater of Windows 10, he can probably still boot with version 1709 install media and convert the disk to GPT using MBR2GPT.EXE.

    Even prior to the release of MBR2GPT, there were ways to convert back and forth, such as by booting a Ubuntu Live USB and running Gparted.  I once made the mistake of converting my old Dell Legacy BIOS laptop hard drive to GPT and had to switch it back before I could boot Windows again.  Gparted worked to fix that without losing anything.

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  4. Anonymous
    2018-03-06T17:05:14+00:00

    Hi Don -

    My Windows 10 build number is 10240 - does this sound correct?  And, yes, Windows does start correctly but it will not update.  Does this help you to help me?

    Doyle

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  5. Anonymous
    2018-03-06T15:48:56+00:00

    Thank You Don -

    I am running Windows 10 on a newer Dell Inspiron laptop.  I just finished a call with Microsoft and they said, I would need to re-format my hard drive and of course doing that would wipe all my files out.  I really want to try getting updates to work without doing a clean install.  You are saying there is a workaround.  Any more info would be helpful.  I am so saddened by all this.

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