Kicad Version (5.1.9)-1
Host OS: Ubuntu 20.04.2. LTS
VM: Oracle VirtualBox 6.1.16 r140961 (Qt5.12.8)
Guest OS: Windows 7 Pro 64 bit
When running under a VirtualBox VM, Kicad appears to have the same QT5 / OpenGL issue which exists in FreeCad, where a black screen will be displayed when opening a schematic or PCB.
Solution is to copy the Mesa3D opengl32.dll (32 or 64 bit, depending on Win7 version) into the Kicad/Bin folder.
More specifically, on page 3 about 1/3 way down by user Build-O-Matic: