Remova o repositório incorreto com
sudo add-apt-repository -r ppa:linuxgndu/adt-raring
e atualize suas fontes:
sudo apt update
Eu atualizei meu Ubuntu 16.04 por sudo apt update
e encontrei este problema.
suraj@UTM-600001420:~$ sudo apt update
Hit:1 http://ppa.launchpad.net/gerardpuig/ppa/ubuntu xenial InRelease
Hit:2 http://in.archive.ubuntu.com/ubuntu xenial InRelease
Ign:3 http://ppa.launchpad.net/linuxgndu/adt-raring/ubuntu xenial InRelease
Hit:4 http://in.archive.ubuntu.com/ubuntu xenial-updates InRelease
Hit:5 http://ppa.launchpad.net/sunab/kdenlive-release/ubuntu xenial InRelease
Hit:6 http://in.archive.ubuntu.com/ubuntu xenial-backports InRelease
Hit:7 http://archive.canonical.com/ubuntu xenial InRelease
Hit:8 http://in.archive.ubuntu.com/ubuntu xenial-security InRelease
Hit:9 http://ppa.launchpad.net/teejee2008/ppa/ubuntu xenial InRelease
Hit:10 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial InRelease
Err:11 http://ppa.launchpad.net/linuxgndu/adt-raring/ubuntu xenial Release
404 Not Found
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/linuxgndu/adt-raring/ubuntu xenial Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
Como consertar isso?
Remova o repositório incorreto com
sudo add-apt-repository -r ppa:linuxgndu/adt-raring
e atualize suas fontes:
sudo apt update