The file is above the 4 GB limit for files that can be stored on FAT32 formatted volumes.
After some research, I determined the error message is probably referring to the sources/install.wim file on the ISO which is 4.4 GB in size. The result was the error message shown below. I am currently running High Sierra (macOS 10.13.6). I tried using the Boot Camp Assistant on my iMac (21.5-inch, Late 2013) to create a USB flash drive Windows 10 installer. The downloaded file was named Win10_1809Oct_English_圆4.iso. I downloaded the Windows10 October 2018 Update iso file from the Microsoft website Download Windows 10 Disc Image (ISO File).
