Se você está tendo problemas com a atualização do Ubuntu 16.04, corrija a sua sua Sources.list aqui.
Sources.list padrão do Ubuntu 16.04. LTS Xenial Xerus 64 bits.
[Ubuntu 16.04.3 LTS _Xenial Xerus_ – Release amd64 (20170801)]/ xenial main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://br.archive.ubuntu.com/ubuntu/ xenial main restricted
# deb-src http://br.archive.ubuntu.com/ubuntu/ xenial main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://br.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
# deb-src http://br.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://br.archive.ubuntu.com/ubuntu/ xenial universe
# deb-src http://br.archive.ubuntu.com/ubuntu/ xenial universe
deb http://br.archive.ubuntu.com/ubuntu/ xenial-updates universe
# deb-src http://br.archive.ubuntu.com/ubuntu/ xenial-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://br.archive.ubuntu.com/ubuntu/ xenial multiverse
# deb-src http://br.archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://br.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
# deb-src http://br.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://br.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src http://br.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
## Uncomment the following two lines to add software from Canonical’s
## ‘partner’ repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu xenial partner
# deb-src http://archive.canonical.com/ubuntu xenial partner
deb http://security.ubuntu.com/ubuntu xenial-security main restricted
# deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted
deb http://security.ubuntu.com/ubuntu xenial-security universe
# deb-src http://security.ubuntu.com/ubuntu xenial-security universe
deb http://security.ubuntu.com/ubuntu xenial-security multiverse
# deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse
Para editar o arquivo digite o seguinte comando:
sudo gedit /etc/apt/sources.list
Salve as mudanças feitas e feche o editor.
Agora entre como o seguinte comando para atualizar os repositórios:
sudo apt update
Agora verifique as atualizações com o comando:
sudo apt upgrade
Para visualizar o arquivo entre no terminal e digite:
cat /etc/apt/sources.list
Desabilitando os repositórios Multiverse e Universe.
Obs.: Pacotes no repositório Multiverse frequentemente têm questões de licenciamente que não permitem que eles sejam distribuídos com um sistema operacional livre e podem ser ilegais na rua região.
Obs.: Esteja ciente que nem o repositório Universe ou o Multiverse contém pacotes oficialmente suportados. Em particular, talvez não seja seguro atualizar para estes pacotes.
Por padrão, os repositórios Universe e Multiverse são habilitados se desejar desabilitá-los edite /etc/apt/sources.list e comente as seguintes linhas:
deb http://archive.ubuntu.com/ubuntu xenial universe multiverse
deb-src http://archive.ubuntu.com/ubuntu xenial universe multiverse
deb http://us.archive.ubuntu.com/ubuntu/ xenial universe
deb-src http://us.archive.ubuntu.com/ubuntu/ xenial universe
deb http://us.archive.ubuntu.com/ubuntu/ xenial-updates universe
deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-updates universe
deb http://us.archive.ubuntu.com/ubuntu/ xenial multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://us.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
deb http://security.ubuntu.com/ubuntu xenial-security universe
deb-src http://security.ubuntu.com/ubuntu xenial-security universe
deb http://security.ubuntu.com/ubuntu xenial-security multiverse
deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse
Fonte: Help Ubuntu
Até a próxima!