How to do a clean install with a USB-stick booter

dortmunder said:

My mobo has the option of UEFI or BIOS. My system is currently BIOS. If I clean install and want to have UEFI then am I right in saying that I need to enter the BIOS, change boot order to 'USB' and set it to UEFI?

This afternoon I used a USB drive to clean installed 1703 in UEFI mode (for the first time), and I had to set 'Windows Boot Manager' as the first boot device after the installation. Luckily, all files in drive D: remained there after I converted MBR to GPT.

NavyLCDR said:

Yes, the MCT will create a USB flash drive that will work in both UEFI and legacy BIOS computers.

I created a bootable USB drive without using MCT according to
How to make active@boot disk bootable on uefi/gpt? - Solved - Windows 10 Forums
You were one of those who answered my questions there. Thanks a lot!

You have to be careful how you convert a drive containing a data partition from MBR to GPT and to keep your data a third party program like MiniTool Partition Wizard must be used. If you use the Windows standard diskpart commands, the physical drive must be erased entirely and the normal sequence of commands is "clean" followed by "convert gpt". The clean command wipes all the partitions off the drive.

dortmunder said:

"...and also make the usb bootable to UEFI (GPT) when you make the bootable usb." The Media Creation Tool makes no mention of this, it's just a case of choosing USB or disc and then the Tool goes ahead and does it. Does the Tool automatically give you a UEFI compatible USB/disc does anyone know?

That's if you use Rufus, did not see you we're using the MS tool.

NavyLCDR said:

MiniTool Partition Wizard must be used.

I used neither MiniTool Partition Wizard nor Diskpart to convert my HDD from MBR to GPT.
I used Gdisk on a Linux Live DVD instead, as I had already mentioned in this post last month.
My data partition remains safe and sound.

NavyLCDR said:

You have to be careful how you convert a drive containing a data partition from MBR to GPT and to keep your data

I don't have to be careful because I already did it successfully.

anonjwm said:

That's if you use Rufus, did not see you we're using the MS tool.

I used neither to create my bootable USB drive.

A quick recap then, if I may. To clean-install a UEFI based Win10 on a BIOS based Win10 I need to:

Use Media Creation Tool to make a bootable USB stick. (The MCT will create a USB flash drive that will work in both UEFI and legacy BIOS computers.)

Go into the BIOS and A) change boot order to USB drive and B) change its settings to UEFI.
Start the installation.

When prompted, allow the change to GPT. (As it is a clean-install, and the SSD is only for the OS,I'm not concerned about losing data so no need for a third party program like MiniTool Partition Wizard).

Does that sound right? Thanks for your time.

Sounds good except for this bit...

dortmunder said:

When prompted, allow the change to GPT. .

The installation doesn't actually prompt you to change to GPT.

When you get to the bit during the installation that says "Where do you want to install Windows?" remove all the partitions and try to carry on. If it is GPT this will work.

If it is formatted MBR you might get a message "Can't install windows on this disk". Normally you don't get this message if you delete all the partitions but you might.

If you do you can press Shift+F10 to get a command box then enter:

diskpart
list disk
select disk 0 (Changing the 0 for a different disk number if required).
clean
convert gpt
exit

And then carry on.

dortmunder said:

change boot order to USB drive

Yesterday I did not change the boot order.
I just selected 'UEFI：PNY OU3 3.0' in the boot menu below.

After I had converted MBR to GPT and installed Windows in UEFI mode, the following problem arose when it rebooted.

Disconnecting other drives did not solve the problem, but selecting 'Windows Boot Manager' as the first boot device did.