I got the same issue when I added 2 repositories Vivid and Wily
My system is Trusty based and I have set APT::Default-Release "trusty"; in /etc/apt/apt.conf
I fix it by upgrading apt with command
sudo apt-get -t vivid install apt/vivid
I got the same issue when I added 2 repositories Vivid and Wily
My system is Trusty based and I have set APT::Default- Release "trusty"; in /etc/apt/apt.conf
I fix it by upgrading apt with command
sudo apt-get -t vivid install apt/vivid