title: copying file under root got failed in OS X El Capitan 10.11
body: <p>I'm trying to copy under root file into /System folder. It works well on all previous OS X version but not on El Capitan 10.11</p>
  
  <p>Here how I copy file under root in terminal:</p>
  
  <pre><code>MACMINI:~ myusername$ sudo su -
  MACMINI:~ root# cp /Users/myusername/Desktop/myfile.plist /System/Library/LaunchDaemons/
  </code></pre>
  
  <p>As result I receive an error:</p>
  
  <pre><code>cp: /System/Library/LaunchDaemons/myfile.plist: Operation not permitted
  </code></pre>