Why do you want to do that? That's your boot partition (the thing the motherboard looks at to determine where the rest of the OS is). Changing that format scheme could break your install.
The EFI system partition is formatted with a file system whose specification is based on the FAT file system and maintained as part of the UEFI specification
What's the exact error message you receive from fortnight? That's what you need to resolve, cause there's nothing wrong with what you've originally posted, but if you do find a way to do what you originally asked you WILL break your system.
I resolved it, the default download location was in the system file for some reason, I had to manually set the download location to the C: drife for it to work