

Obviously, you can't install Windows 10 to a USB flash drive or external hard drive using the Windows Setup wizard.

Setup does not support configuration of or installation to disks connected through a USB or IEEE 1394 port." When you click on that warning message, it says "Windows cannot be installed to the disk.

Windows Setup will display the warning message "Windows can't be installed on drive", as shown in the figure below. If you try to install Windows 10 onto your USB drive in the typical way, that is, boot your computer from a Windows 10 installation media and then select your USB drive as the installation destination, you will end up with failure.
