**System Information**
Operating system:Win 10
Graphics card: GTX 1050 4 gb
Intel core i7 7700HQ
8 GB RAM
**Blender Version**
2,8
**Short description of error**
When I press F12 to render it freeze on building BVH freeze all pc. when I render on viewport it render good.
It happen only when I active particle hair . When I disable it render normal