title: Xcode failed to install
body: <p>I am trying to install <a href="http://en.wikipedia.org/wiki/Xcode" rel="noreferrer">Xcode</a> 4.2 on my <a href="http://en.wikipedia.org/wiki/Macintosh" rel="noreferrer">Mac</a> system having OS version 10.6.8.
  Actually, I removed the Xcode from the system and tried to reinstall it.</p>
  
  <p>I quit <a href="http://en.wikipedia.org/wiki/ITunes" rel="noreferrer">iTunes</a> before installing it, and I have enough free space on disc (111&nbsp;GB). Below is a screenshot of the error. What should I do?</p>
  
  <p><img src="https://i.stack.imgur.com/c4ktJ.png" alt="Screnshot"></p>