Windows-10 in Virtualbox install

[Konrad Eisele]

Hello, I tried to install Windows-10 in Virtualbox 4.3.30 on Freebsd 10.2.
It starts up and shows the blue 4 tile logo, but then it doesnt continue.
Normally it should show the circle with the dots spinning round, however
Virtualbox loops at 100%.
I then compiled Virtualbox 5.0 on FreeBsd (with some patching) and
got Virtualbox-5.0 to start, however the behaviour is almost the same
only that it loops at ~50% now. (I guess that Windows 8.1 will be the same).
Windows-7 starts up ok.
I'm not so familiar with Virtualization and wonder weather someone
knows what is missing in the FreeBsd driver so that Windows 10 cannot
start up. Does anyone know what magic Windows does in the beginning?
It does something that is emulated in Linux or OSX. Here Windows 10
boots.
On FreeBsd, when loading a Windows-10 VBox image created in Linux it starts
and hangs like when installing from CD, however when restarting the machine,
next time it writes "trying automatic recovery", so it has recorded that
it has started once. Then it hangs again.
I know  Bootloader stuff is lowlevel and esoteric and I guess I cannot
fix this myself, but maybe someone can give me a hint where to look
maybe point to the patch that did the trick in the linux driver :-)
// Greetings Konrad