title: ROS Installation E: Unable to correct problems, you have held broken packages
body: <p>I am trying to install ROS Indigo. I did the following steps:</p>
  
  <pre><code>$ sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu xenial main" &gt; /etc/apt/sources.list.d/ros-latest.list'
  
  $ sudo apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
  
  $ sudo apt-get update
  
  $ sudo apt-get install ros-indigo-desktop-full
  </code></pre>
  
  <p>When I executed the last line, I've received the following error:</p>
  
  <pre><code>Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  Some packages could not be installed. This may mean that you have
  requested an impossible situation or if you are using the unstable
  distribution that some required packages have not yet been created
  or been moved out of Incoming.
  The following information may help to resolve the situation:
  
  The following packages have unmet dependencies:
   ros-indigo-desktop-full : Depends: ros-indigo-desktop but it is not going to be installed
                             Depends: ros-indigo-perception but it is not going to be installed
                             Depends: ros-indigo-simulators but it is not going to be installed
                             Depends: ros-indigo-urdf-tutorial but it is not going to be installed
  E: Unable to correct problems, you have held broken packages.
  </code></pre>
  
  <p>I have tried <a href="https://stackoverflow.com/a/45606925/8977639">this</a> suggested solution, however it did not work. </p>