iATKOS | United Kingdom

I have downloaded High Sierra using the Mac App Store, downloaded Unibeast from the website, and formatted my USB correctly.

I get as far as selecting the OS on Unibeast but High Sierra is the only one there and is greyed out.

I have tried deleting and redownloading Sierra but it has not worked and I have closed and opened Unibeast multiple times... Please does anyone have any other ideas?

(I am running this off Mac OS in Virtual Box but it lets me use everything properly - even formatting the USB, so I don't see how that would affect it.)