Kali linux 2.0 64 bit Virtual box black screen at the end of instalation

I have posted one thread but it was deleted because there was alredy post about this issue . I couldnt it . I asked for help but no response . Can someone help me . So when i complete the instalation on virtual box at the end it goes black and stops there . Can someone help me

Did you install GRUB?
You cannot do next -> next -> Next, else it will fail.
Make sure to you select '/dev/sda' (rather than none).

thanks i instaled it