Virtualbox-guest-additions-iso [exclusive] -

Why? The communication between the host and the Guest Additions occurs through a (VMMDev, PCI device with vendor ID 0x80EE). This interface has a version number. When the host’s VMMDev implementation (part of VirtualBox) and the guest’s driver speak different protocol versions, features break—often silently. Symptoms include:

The VBoxGuestAdditions.iso is a disk image containing software drivers and system applications designed to be installed inside a guest operating system. Unlike the VirtualBox Extension Pack, which is installed on the host machine, these additions are guest-specific and bridge the gap between the virtualized environment and the host hardware. virtualbox-guest-additions-iso