When installing Win 10 Pro on my newly built system (from a USB key purchased from Microsoft) I somehow managed to format the system drive (Samsung SSD 970 EVO NVMe m.2) as MBR instead of GPT. As a result, I can only boot Windows into Legacy BIOS Mode, not UEFI. I would like to fix this. I believe I will have to reinstall Windows from scratch. I know that there is a utility called MBR2GPT that can convert the drive from MBR to GPT, but since this is a brand new install, I don't mind starting afresh.
What is the best way to go about this? This site (https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-8.1-and-8/dn336946(v=win.1...
) says to:
1. Turn off the PC, and put in the Windows installation USB key.
2. Boot the PC to the USB key in UEFI mode.
3. When choosing an installation type, select Custom.
4. On the Where do you want to install Windows? screen, select each of the partitions on the drive, and select Delete. The drive will show a single area of unallocated space.
5. Select the unallocated space and click Next. Windows detects that the PC was booted into UEFI mode, and reformats the drive using the GPT drive format, and begins the installation.
Is this a good approach? I'm not sure I fully understand step 2. How can I be sure to boot my Strix Z390-E into UEFI mode? Should I clear the CMOS? Restore BIOS to default settings? On a forum for MSI motherboards I read that the way to ensure booting into UEFI mode was to "press , confirm, set "SETTINGS \ Advanced \ Windows OS Configuration \ Windows 10 WHQL Support"="Enabled." I understand that this procedure won't work on my ASUS board, but I would be grateful for a straightforward explanation of how to get my Z390-E to boot into UEFI mode.
Thanks so much for your advice.
ASUS ROG Strix Z390-E | Intel i7-8700K | Corsair Vengeance LPX 32 GB DDR4-2666 | EVGA GeForce GTX 1070 Ti 8 GB FTW ULTRA SILENT | Samsung 960 EVO 500 GB M.2-2280 SSD | Western Digital Black 6TB | Cryorig H7 | Fractal Design Define R6 Gunmetal TG ATX | SeaSonic FOCUS Plus Gold 650 W 80+ | Windows 10 Pro 64-bit