VirtualBox Guest Additions in VirtualBox by clicking Devices -> Insert Guest Additions CD Imagesudo mount /dev/cdrom /mnt/cdromsudo ./VBoxLinuxAdditions.runsudo shutdown -r nowsudo mount –t vboxsf {host shared folder name} {guest mount directory}While using Ubuntu Server 16.04.3 LTS:
/etc/fstab entries for folders you want to mount
PlexMedia /mnt/plex-media vboxsf defaults,uid=1000,gid=1000 0 0vboxsf to a line of its own in /etc/modulessudo usermod -a -G vboxsf kevin