How-to: Guest Additions for VirtualBox 4.3 - Debian 7 (or any of it's derivatives)

Guest Additions is picky about dkms and wanting to build kernel modules. Open the Root Terminal: apt-get install build-essential module-assistant Once installed, the module-assistant can fetch the Linux headers: m-a prepare Have the Guest Additions CD image loaded in your virtual CD drive (VirtualBox "Devices" menu), but don't expect Autorun to work, it only returns "Error autorunning software. Cannot find the autorun program." Don't ask. Instead, still in the Root Terminal, run: sh /media/cdrom/VBoxLinuxAdditions.run and follow the installation prompts. You can then reboot with the 3D Acceleration, display resize and auto-resolution working again.