When I try to make sudo apt-get update I get this:

W: Repository "linux.dropbox. com / ubuntu serena Release ”does not contain the Release file.

N: The data from this repository cannot be authenticated, and therefore potentially unsafe to use.

N: See the apt-secure help page (8) for creating a repository and setting up a user.

E: Failed to get linux.dropbox. com / ubuntu / dists / serena / main / binary-amd64 / Packages 404 Not Found [IP: 54.192.98.213 80]

E: Some index files did not download. They were ignored or old versions were used instead.

How to fix it?

When you type tail -n 100 /etc/apt/sources.list /etc/apt/sources.list.d/*; lsb_release -a tail -n 100 /etc/apt/sources.list /etc/apt/sources.list.d/*; lsb_release -a come this:

 ==> /etc/apt/sources.list <== #deb cdrom:[Linux Mint 18.1 _Serena_ - Release amd64 20161213]/ xenial contrib main non-free' ==> /etc/apt/sources.list.d/additional-repositories.list <== deb http://linux.dropbox.com/ubuntu serena main ==> /etc/apt/sources.list.d/official-package-repositories.list <== # Do not edit this file manually, use Software Sources instead. deb http://packages.linuxmint.com serena main upstream import backport #id:linuxmint_main deb http://archive.ubuntu.com/ubuntu xenial main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu xenial-updates main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu xenial-backports main restricted universe multiverse deb http://security.ubuntu.com/ubuntu/ xenial-security main restricted universe multiverse deb http://archive.canonical.com/ubuntu/ xenial partner ==> /etc/apt/sources.list.d/ubuntu-wine-ppa-xenial.list <== deb http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu xenial main deb-src http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu xenial main ==> /etc/apt/sources.list.d/webupd8team-atom-xenial.list <== deb http://ppa.launchpad.net/webupd8team/atom/ubuntu xenial main deb-src http://ppa.launchpad.net/webupd8team/atom/ubuntu xenial main ==> /etc/apt/sources.list.d/wine-wine-builds-xenial.list <== deb http://ppa.launchpad.net/wine/wine-builds/ubuntu xenial main deb-src http://ppa.launchpad.net/wine/wine-builds/ubuntu xenial main No LSB modules are available. Distributor ID: LinuxMint Description: Linux Mint 18.1 Serena Release: 18.1 Codename: serena
  • one
    You do not know what code 404 means? This means that the page was not found, i.e. there is no more data. You don't download anything from there anymore. Remove this source from apt - ArchDemon
  • How to fix it. Recently moved to Linux - user237272
  • Attach the output of the command tail -n 100 /etc/apt/sources.list /etc/apt/sources.list.d/*; lsb_release -a tail -n 100 /etc/apt/sources.list /etc/apt/sources.list.d/*; lsb_release -a - aleksandr barakin
  • copy and paste the text , please. All the necessary information should be in the text of the question, and not on third-party resources (and even, probably, a picture). - aleksandr barakin

2 answers 2

A non-existent repository http://linux.dropbox.com/ubuntu/dists/selena described on your system in the file /etc/apt/sources.list.d/additional-repositories.list .

it is better to remove it:

 $ sudo rm /etc/apt/sources.list.d/additional-repositories.list

the rest of the package sources (even the “left” ones from ppa.launchpad.net ) seem to work, so (after deleting the file) the update of the list of packages should go fine:

 $ sudo apt-get update

    For Linux Mint Serena this line will fit:

    Add the address of the turnip:

     echo deb http://linux.dropbox.com/ubuntu xenial main '#Dropbox' > /etc/apt/sources.list.d/dropbox.list

    Add gpg-key:

     wget https://linux.dropbox.com/fedora/rpm-public-key.asc -O - | apt-key add -

    All from under the superuser.