Windows 10: Win10 repair install with a MBR USB stick while C: is GPT (UEFI)

My C: is GPT, running fully in UEFI mode, I believe. This is Intel NUC6i5SYK. I'm trying to do a repair install. So I tried making the Win10 bootable USB with Rufus (and Windows USB Download Tool). Only making it in MBR it boots. If GPT, it doesn't boot.

1) If I repair install while the USB is in MBR mode, is this fine and C: will stay fully GPT and UEFI?

2) Why can't Rufus make the GPT stick boot? (I downloaded also Easy2Boot but I didn't try that yet.)

:)

 

Convert Windows 10 MBR to GPT (UEFI)?

In reviewing my Windows 10 Pro (64-bit) system I noted that the Secure Boot Status is showing as "unsupported". Investigating further, it appears either the GPT partition for booting using UEFI (is Secure Boot) has become corrupt or my installation was
never installed for Secure Boot. My Windows 10 install is an auto-upgrade from a Windows 8.1 install.

Is there a way to convert the MBR to GPT without doing a fresh install? I do have a USB recovery drive built at a point I believe I had indications Windows was booting from a GPT (UEFI) partition. In fact, the USB recovery drive shows as being a UEFI drive.

Any suggestions will be appreciated!

Thanks!

 

GPT vs MBR for SSD OS Disk ? (win7 install)

You can use UEFI with MBR and GPT.

Yes.

 

Is it possible to install Windows 10 in UEFI mode using the original USB stick?

Hi,

I would like to know whether it is possible to use the USB stick supplied with the full version of Windows 10 to install the system on a disk configured to use the GPT (rather than MBR) partition style.

I am asking because the guidelines from Windows Setup: Installing using the MBR or GPT partition style stress that to install Windows on a UEFI disk, it is necessary to boot the setup medium in UEFI mode as well. However, the original
USB stick seems to be using the MBR partition style. In any case I can't boot from it when the PC is configured to boot first from a "UEFI USB Key"; booting only succeeds when the firmware is set to boot first from a "USB Key". But then the installer converts
the system disk to MBR even if it was previously set to use GPT.

Does this mean that in order to install the system on a GPT disk, I cannot use the original USB stick, but I need to download the Windows 10 ISO file and write it to another USB stick formatted using the GPT partition style?

Best regards,

Wojtek