The Windows ISO file is too large – Boot Camp Assistant creates a [X] GB installer partition which will contain the files present on the Windows 10 ISO as well as the Boot Camp Support software.

If you want to convert a FAT32 drive to NTFS file system without losing data, you can use the convert command line or a third-party converter tool.

FAT32, which stands for the 32-bit version of Microsoft’s file allocation system, is far from the go-to option in Windows.