1

whenever I run : 

sudo apt-get update

I get this message below: 

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.

I used 

sudo nano /etc/apt/sources.list

and comment or remove lines that include cdrom. eg:

deb cdrom:[Ubuntu-Server 16.04 LTS Xenial Xerus - Release amd64 (20160420.3)]/ xenial main restricted>

I was be able to remove it. when I ran sudo apt-get update , got the error message below.

W: The repository 'http://ppa.launchpad.net/ubuntu-on-rails/ppa/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 http://ppa.launchpad.net/ubuntu-on-rails/ppa/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.

could anyone shed some light on this please ? Thanks a million in advance.

Panther
  • 102,067
Dil Azat
  • 73

1 Answers1

1

The ppa you are using does not have packages available for 16.04, that is the meaning of the 404 error.

Disable the ppa or contact the maintainer.

See also How can I fix a 404 Error when using a PPA or updating my package lists?

Community
  • 1
Panther
  • 102,067
  • I can disable the ppa easily. However, I need it for programming purposes. if I were to contact the maintainer how would I go about it ? Thank you so much – Dil Azat Oct 13 '16 at 16:22
  • @DilAzat Try https://launchpad.net/~ubuntu-on-rails – Elder Geek Oct 13 '16 at 16:25
  • From https://launchpad.net/~ubuntu-on-rails you can file a bug report, contact the team, post to the mailing list, etc. If you need the package, and there is no ppa, you will have to compile from source. – Panther Oct 13 '16 at 16:27