Changing BIOS Legacy to UEFI with clean install? Will it work?

[CrazyMav]

I have a Toshiba that I wanted to run Windows 10 Pro, the OEM was Home; I have Windows 7 Pro and decided to install that and do the upgrade and then a clean install, I needed to run Legacy Mode to install Windows 7, after the install and upgrade I wanted to change it to UEFI but since that isn't possible to do without doing a clean install or a recovery media device, I can't and don't want to do that.

If I do a clean install of Windows 10 Pro, from a USB and delete all partitions, will Windows 10 activate?

I have done so on my desktop, it has worked, BUT when I did it on my Toshiba after it activated to Windows 10 Home, it failed to activate during the clean install. What are the chances it won't activate this time? The process from Windows 7 to 10 isn't fast and I don't want to have to do that again..

 

[Slashgeek]

If you do a clean install of Windows 10 Pro AFTER a successful upgrade of Windows 7 Pro to Windows 10 Pro, and then activated after connecting to the internet, then Windows 10 will have successfully created a hardware snapshot of your computer's configuration, which it will use to self-activate. As long as there are no major hardware changes like a motherboard change, you will be fine

 

[CrazyMav]

Well I did do a clean install of Windows 10 Pro just now, changed the BIOS mode to UEFI with Secure Boot, and it successfully activated.

BUT, I have done what you said, Slashgeek, and I have had it not activate. I went through Microsoft's support team on that issue and they told me to just do the install again, from Windows 8 Home to Windows 10 Home..