Hello, I am brand new to the mackintosh world and i decided to convert my desktop. I have the current version of Unibeast and macOS Sierra 10.12.15 and this problem occurs. Each time I download a clean version of Sierra from the apple store it doesn't work and I haven't gotten it to work yet. If anyone has any tips to help it would be greatly appreciated I also have a GTX 560 graphics card. Thanks!!