Q. I'm trying to create a bootable USB drive for UEFI systems but the install.wim file is too large. What can I do?
A. UEFI systems cannot boot from NTFS and instead the device needs to be formatted FAT32 which has a 4GB maximum size. The install.wim file on the media is larger than this file size limit. The solution is to split the WIM into multiple files using DISM. This is documented at https://msdn.microsoft.com/en-us/windows/hardware/commercialize/manufacture/desktop/split-a-windows-image--wim--file-to-span-across-multiple-dvds.