I build from the template in 4.9, and just change the matrial of the floor and the wall.
I just create a new blank project. Build the light. And then, stop at 0% again.
I had waited a day and a night. 0%. Not go to 1%.
I use mac. No directX support.
OS 10.11.1 (15B17c)
2.8 GHz Intel Core i7
16 GB 1600 MHz DDR3
Intel HD Graphics 4000 / NVIDIA GeForce GT 650M