Soo...here's a weird issue and I'm dead serious...lol
So if you are installing Windows 10 as a vm, you may get an error:
"Windows cannot read the product key from the unattended answer file"
To fix that, go into the vm settings, and disconnect the floppy drive. Then it'll run the set up. lol...
I only post this because I was trying a bunch of complex shit and that simple thing fixed my problem.
This was done on Fusion Pro 7