One thing folks may not realize is the Flash Drive has to be formatted as FAT 32 in order to boot as UEFI.. It also has to be an x64 version of the OS. The tool recommended will create such a flash drive but downloading directly to a Flash Drive can be slow.   Updated Videos:       Clean Install:  
Hi there,  I've really been struggling with this: I'm trying to install Windows 10 from Dell USB drive that I've made bootable, but it's only seen in the legacy options in the one-time boot menu. Secure boot is off and UEFI is enabled. I need the USB to be recognized as UEFI in order to install Windows to boot to UEFI. I'm using Rufus to make the bootable drive and I've tried both MBR and GPT partition scheme for UEFI with no luck. Is there any BIOS settings I need to check?  
Can't install Windows 10 from bootable USB with UEFI - Dell Latitude E7470