The VirtualBox Guest Additions consist of device drivers and system applications that optimize the operating system for better performance and usability. The most useful features of Guest Additions are the installation of drivers for the graphics and seamless mouse capture/release.
Insert the Guest Additions CD Image
Insert -> Insert Guest Additions CD image...
Cancel any automatically run prompt
Activities -> Search -> Terminal
- Change to root
Update and upgrade Debian
apt-get update && apt-get upgrade
Mount the CD
Download the GNU C Compiler (gcc), utility for directing compilation (make), Perl language (perl) & Header files for Linux amd64 configuration (linux-headers-amd64)
apt install gcc make perl linux-headers-amd64
Run the install
Eject the CD
Device -> Optical Drives -> Remove disk from virtual drive