sources\install.wim in recent releases of Windows 10 has exceeded FAT32’s maximum filesize of 4 GiB. If you only boot UEFI systems and you want to use memory sticks for better performance while installing, you must split sources\install.wim into smaller files. Luckily, the dism command can do this for you.

Read More → Split install.wim into install.swm and install2.swm