Blender import error, multiple root bones.

Thanks it works, i am also Unity developer, thinking to move to UE4, already i import my model), i have simple model but i have near 60 anims done for Mecanim controler, with custom skeleton). If any one interested what i dev in Unity see this https://youtu.be/zP424v9lecE, i think to move because i have a lot of bugs with Unity 5, just press start Unity down, change anims Unity down, and e.t.c.). I try dev the some mechanics in Unreal Engine)

Firstly i have this - multiple root bones error

f4290ed0b7363348bc1cd3c98012cbda438208e0.png

Then i change it like now:

Also i am create tuturial https://youtu.be/Pq7rOXc6ZQs