This question already has an answer here:
- Force update from unsigned repository 5 answers
I found an outdated solution for installing Adobe Reader here on askubuntu.
I followed the steps but after updating my sources using
sudo apt-get update I am getting the following error:
Hit:1 http://archive.ubuntu.com/ubuntu artful InRelease Ign:2 http://archive.canonical.com precise InRelease Get:4 http://archive.canonical.com precise Release [8,180 B] Get:5 http://archive.canonical.com precise Release.gpg [198 B] Ign:5 http://archive.canonical.com precise Release.gpg Ign:3 http://dl.google.com/linux/chrome/deb stable InRelease Hit:6 http://dl.google.com/linux/chrome/deb stable Release Reading package lists... Done W: GPG error: http://archive.canonical.com precise Release: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5 E: The repository 'http://archive.canonical.com precise Release' is not signed. 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.
What can I do to fix this and get Adobe Acrobat installed?
The question itself is actually not a duplicate since OP wants to install Adobe Acrobat and the old solution was outdated.