Obtendo erros 404 e mais com o sudo apt-get update

Question

Sou completamente novo no Linux.

Executando o Ubuntu 16.04.
Ao executar sudo apt-get update , recebo 404 erros e Failed to fetch ... juntamente com muito mais. Eu não sei o que é isso nem como consertá-lo.

Isto é o que parece:

Err:16 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 Packages
  404  Not Found
Err:18 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main i386 Packages
  404  Not Found
Err:25 http://ppa.launchpad.net/upubuntu-com/gtk3themes/ubuntu xenial/main amd64 Packages
  404  Not Found
Err:26 http://ppa.launchpad.net/upubuntu-com/gtk3themes/ubuntu xenial/main i386 Packages
  404  Not Found
Fetched 529 kB in 5s (95,5 kB/s)
Reading package lists... Done
W: The repository 'http://ppa.launchpad.net/tualatrix/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.
W: The repository 'http://ppa.launchpad.net/upubuntu-com/gtk3themes/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.
W: GPG error: http://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_15.04  Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5A7D1D38BEB6D886
W: The repository 'http://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_15.04  Release' is not signed.
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: There is no public key available for the following key IDs:
5A7D1D38BEB6D886  
E: Failed to fetch http://ppa.launchpad.net/tualatrix/ppa/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found
E: Failed to fetch http://ppa.launchpad.net/tualatrix/ppa/ubuntu/dists/xenial/main/binary-i386/Packages  404  Not Found
E: Failed to fetch http://ppa.launchpad.net/upubuntu-com/gtk3themes/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found
E: Failed to fetch http://ppa.launchpad.net/upubuntu-com/gtk3themes/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.

    

Answer 1

Esses PPAs ainda não foram atualizados para o 16.04. Você pode esperar ou desativá-los via Updates .