Yesterday, I downloaded VirtualBox 6.0.8 and Kali 2019.2 both the ova and iso for VirtualBox. When trying to install either version, I was getting either a black screen with nothing, or black screen with a blinking cursor. I couldn't get past the GRUB. Disable Hyper-V. That. Was. It. I stumbled across something that made me think to disable it when I ended up downloading VMWare Workstation 15 and even that gave me some weird but totally different error. I figured maybe Hyper-V doesn't play well with it so I disabled it, rebooted, and now Kali is loading perfectly on VMWare AND VirtualBox, both the iso and ova.
My computer is a Dell Inspiron 13 7000 on Windows 10 HOME.
From the Start menu, search for Hyper-V and click on "Turn Windows features on or off". Scroll down to Windows Hypervisor Platform and uncheck it. Reboot when prompted, then try to install Kali again.
I hope this helps someone - I was going nuts for 2 days trying to figure it out.