: When using apt-get or some other GUI package management application to install a new package on Ubuntu or Debian Linux the following error message appears:
W:Failed to fetch cdrom://Ubuntu 14.04 LTS _Trusty Tahr_ - Release amd64 (20140416)/dists/trusty/main/binary-amd64/Packages
Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs


: When Ubuntu or Debian Linux are installed using CD-ROM media this system will retain CD-ROM in its /etc/apt/sources.list file as a repository source. To avoid this error message is to re-insert your Ubuntu/Debian Linux installation media before running apt-get command or remove/comment this CD-ROM repository source directly from /etc/apt/sources.list. Using your text editor open /etc/apt/sources.list file and comment or remove lines that include CD-ROM. eg:
deb cdrom:[Ubuntu 14.04 LTS _Trusty Tahr_ - Release amd64 (20140417)]/ trusty main restricted

Another alternative when GUI is available is to run "Software & Updates" application and remove check from any check-box next to "Cdrom with Ubuntu".
software & updates - remove CDROM apt-get source