Masalah dengan sudo apt get update: The repository cdrom ... tidak memiliki file Release

Setiap kali saya mencoba memperbarui (menggunakan sudo apt-get update) Ubuntu saya, saya mendapatkan masalah ini:

W: The repository 'cdrom://Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1) xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: The repository 'ppa.launchpad.net/kirillshkrogalev/ffmpeg-next/ubuntu xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch cdrom://Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)/dists/xenial/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
E: Failed to fetch cdrom://Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)/dists/xenial/main/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs
E: Failed to fetch ppa.launchpad.net/kirillshkrogalev/ffmpeg-next/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found
E: Failed to fetch ppa.launchpad.net/kirillshkrogalev/ffmpeg-next/ubuntu/dists/xenial/main/binary-i386/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.

Bagaimana saya bisa memperbaikinya?
Saya menggunakan Ubuntu 16.04 LTS

Untuk mengatasi masalah ini dari terminal Anda harus menghapus / berkomentar sumber repositori CD-ROM ini langsung dari /etc/apt/sources.list

 sudo nano /etc/apt/sources.list

dan komentar atau hapus baris yang menyertakan cdrom . misalnya:

deb cdrom:[Ubuntu-Server 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.3)]/ xenial main restricted

Coba ini:
Buka Software & Updates dan di tab Software Ubuntu hapus centang Cdrom dengan Ubuntu 16.04 LTS 'Xenial Xerus' di bawah bagian Installable from CD-ROM / DVD .