If you have an internet connection, you can safely comment out the line starting with deb cdrom: .... in the file /etc/apt/sources.list. You can edit this file with the command: sudo gedit /etc/apt/sources.list and simply prepend this line with the #…
Issue: When you install Virtualbox 5.1 on Ubuntu 16.04, you may encounter following error: root@XIAYE-NA1:~/Downloads# apt install virtualbox-5.1 Reading package lists... Done Building dependency tree Reading state information... Done virtualbox-5.1…