Stovie,
Welcome to LQ forums.
Open a Terminal and perform the following commands separately:
Code:
sudo apt update
sudo apt-get install virtualbox-dkms
sudo apt-get install linux-headers-generic
You also need to install
VirtualBox Guest Additions:
Open
Devices menu (at the top) in VirtualBox and choose
Insert Guest Additions CD image
When you login you should see the CD image in the background. Open the Terminal Emulator again and run the VBoxLinuxAdditions.run file.
Code:
sudo /media/your_username/Vbox_Gas_6.0.14/VboxLinuxAdditions.run
This link should help:
http://www.fixedbyvonnie.com/2015/07.../#.XcMGDtHgobz
If that doesn't work start again from scratch.
Did you download VirtualBox from here:
https://www.virtualbox.org/wiki/Linux_Downloads