I have this problem too. It is because i have installed OS X in UEFI and could not install windows in UEFI so a short fix for me is that i have put my windows HDD in second boot order ( bios configuration) and when Clover boot loader shows up I choose Exit clover so it boots from the second boot...
I decided to share my experience working with this motherboard from a while now
-8 GB or more USB drive
-A working Hackintosh or A real mac (this is needed to make the unibeast drive)
-Yosemite.app from App Store
-El Capitan post installation...
I updated through app store from 10.10.3 to 10.10.5
I needed to start from the usb install drive and chose Macintosh HD from it, otherwise it was freezing upon restart.
The update went smooth. Just had to re install audio through multibeast as usual Just after a reboot and unplugged the Usb...
What you will need
A fully working Mac (or Hackintosh) To make the Unibeast thumb drive
Maverick 10.9.1 From the app store (on your real mac or Hackintosh)
Multibeast 6.0.1 Maverick edition
Chimera 2.2.1 (I know its in Multibeast but i prefer to use the package instead)...