Boot Camp refuses to install Windows 10, "The installer disc could not be found."

I have a mid-2014 MacBookPro 15" Retina. According to Boot Camp Help, this model should install Windows 10 64-bit from an ISO file, not from a USB flash drive.

I have the MacBook connected via Ethernet to a cable modem. A speed tests shows 65Mbps download speed.

I bought Windows 10 from Microsoft for $119.95 and downloaded it to my Downloads folder. The file is called Win10_1511_English_x64.iso. Disk Utility doesn't show that the ISO file is mounted.

I plugged in a new 8GB flash drive, formatted to MS-DOS FAT.

I started Boot Camp Assistant. The first screen just has general instructions.

The second screen has three checkboxes.

The first checkbox is for making a USB install drive. Apple says that my MacBook doesn't need a USB install drive so I unchecked this.

The second checkbox is for "Download the latest Windows support software from Apple." When I check this and then "Continue," it goes to a new window called "Task Status." This says "Saving Windows support software..." This takes about twenty minutes. When it finishes it asks me to enter my password, then says "The installer disc could not be found."

If I leave the first two checkboxes unchecked and check "Install Windows 7 or later version" and "Continue," it says "The installer disc could not be found."

This suggests that Apple's instructions are incorrect, my MacBook apparently requires a USB installer drive ("disk").

I then checked the first checkbox, "Create a Windows 7 or later version install disk." This then checks the second checkbox, "Download the latest Windows support software from Apple." I click "Continue."

The next screen is titled "Create Bootable USB Drive for Windows Installation." I choose the ISO image file. Then I select the USB drive. I click "Continue" and get this error message: "Your bootable USB drive could not be created. Boot Camp only supports Windows 7 or later installation on this platform. Please use an ISO file for Windows 7 or later installation."

When I open the USB drive I see the following files anf folders:

.fseventsd

.Spotlight-V100

.Trashes

$WinPEDriver$ (folder)

AutoUnattend.xml

BootCamp (folder)

SanDiskSecureAccessV2_win.exec

SanDiskSecureAccessV2.0 (folder)

Total drive usage is about 3GB, with 5GB free.

This suggests that my MacBook successfully created a USB install drive, but Boot Camp Assistant doesn't recognize it.

According to https://support.apple.com/en-us/HT201468, a 16GB flash drive is required. I tried a 16GB flash drive, formatted as MS-DOS FAT with two children, and got this error message: "The USB drive can not be used. Please format the USB drive as single FAT partition." I then reformatted the drive in a LINUX machine with one child, on the theory that children and partitions are related. This results in the error message "The installer disc could not be found."

Questions:

- Can I install Windows 10 from the ISO file without making a USB install drive?

- Can I make a USB install drive?

- If the USB install drive was made correctly, how do I make Boot Camp Assistant recognize the USB install drive?

- Does it need an 8GB or 16GB USB flash drive? Why would it need a 16GB flash drive to store 3GB of data?

- Do I need to restart the computer from the USB installation disk? In the "Startup Disk" preference pane the USB installation drive doesn't appear.

- Do I need to partition the SSD before starting Boot Camp Assistant?