Installed Debian 10.4.0 on it.
From VirtualBox menu select Devices -> Insert Guest Additions CD Image. CD automatically ran but unable to locate the program. Why?
After ran this by
root user, it can be installed
But there is an another problem, restart OS it shown:
VBoxClient: The parent session seems to be non-X11. Exiting...
If resize the window to full screen, it can't change size at all.