So the thing is I'm trying to install Cmake and cmake-curses-gui. I have updated the system with apt-get-update. sudo apt-get install cmake Reading package lists... Done Building dependency tree Reading state information... Done Package cmake is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'cmake' has no installation candidate sudo apt-get install cmake-curses-gui Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package cmake-curses-gui That's strange. Can anyone give some pointers? Pastbin sources.list :- http://pastebin.com/DufycYfZ