title: Probably incorrect release file causing apt-get update to fail
body: <p>I’m installing a VM of Ubuntu 14.04 on my PC.</p>
  
  <p>When I run <code>sudo apt-get update</code>, I get a response:</p>
  
  <pre><code>W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty/Release  Unable to find expected entry 'restricted/source/Sources' in Release file (Wrong sources.list entry or malformed file)
  
  E: Some index files failed to download. They have been ignored, or old ones used instead.
  </code></pre>
  
  <p>I've tried to reinstall the VM and it didn't fix the issue.</p>
  
  <p>Thanks in advance!</p>