In a bit of a problem here. I installed a proprietary nvidia driver on my Ubuntu 16.04 on the Virtual Box. After I have do so, I was not able to get past the login screen. I would input my password, it would look as if it is going to give me the desktop screen but then it would go back to the start screen again and ask me for login details.
I followed the steps here to mess with the grub file through the command line (upstart): 12.04.3 can start only after I press "resume" in rescue mode (every boot) - problem with Nvidia driver
After adding nomodeset and running the update-grub - problem was not solved. So I removed quite splash and now I get the UEFI screen. No idea what that is. And now I am stuck....
NOTE: Fixed the UEFI issue. I had a tick box ticked in the VB settings. But still cannot get past the login screen. Easy solution: is to delete the nvidia driver. But I really do not want to. As I believe my sound stutter on videos is due to absence of the driver.