Install Windows On External Drive -
Running an operating system directly from a portable storage device provides incredible flexibility. You can carry your personalized desktop environment, access your data on broken computers, or bypass restricted workplace systems. However, if you attempt to use a standard installation USB, Microsoft's installer will block you from selecting an external drive.
Open again.
dism /Apply-Image /ImageFile:E:\sources\install.wim /Index:1 /ApplyDir:F:\ install windows on external drive