umount: can't umount /cdrom: Device or resource busy /init: line 7: can't open /dev/sr0: No medium found /init: line 7: can't open /dev/sr0: No medium found umount: can't umount /cdrom: Device or resource busy /init: line 7: can't open /dev/sr0: No medium found /init: line 7: can't open /dev/sr0: No medium found umount: can't umount /cdrom: Device or resource busy /init: line 7: can't open /dev/sr0: No medium found Generating locales (this might take a while)... Generation complete. pwconv: failed to change the mode of /etc/passwd- to 0600 Using CD-ROM mount point /cdrom/ Identifying... [d794acb2fce7afa96a6dc8777b90f4f1-2] Scanning disc for index files... Found 2 package indexes, 0 source indexes, 0 translation indexes and 1 signatures Found label 'Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)' This disc is called: 'Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)' Copying package lists...gpgv: Signature made Wed Apr 20 22:29:18 2016 UTC using DSA key ID FBB75451 gpgv: Good signature from "Ubuntu CD Image Automatic Signing Key " Reading Package Indexes... 0% Reading Package Indexes... Done Writing new source list Source list entries for this disc are: deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted Repeat this process for the rest of the CDs in your set.