title: Can't update Xcode 4.2. Error: please consult var/log/install.log for more details?
body: <p><strong>UPDATE</strong>: Since this question is getting some views, I figured I'd better highlight the fact that <strong>I solved the problem</strong> by simply <strong>re-downloading Xcode from the Mac App Store</strong>. Upon re-installing it even gave me a handy option to delete the previous version and replace it with the new one. Hopefully this helps everyone out there with the same problem! :)</p>
  
  <p>So I'm trying to update my Xcode 4.2 which I downloaded from the app store, but I get this error when I use the 'Install Xcode.app' updater:</p>
  
  <p><img src="https://i.stack.imgur.com/AUBdM.png" alt="enter image description here"></p>
  
  <p>Anyone know what I'm doing wrong or how to fix it?</p>
  
  <p>I'm not really sure what other information I should provide, so please just let me know if you want more info :)</p>
  
  <p>Edit: Here is the full install.log (I think): <a href="http://pastebin.com/GTzkpL3X" rel="nofollow noreferrer">http://pastebin.com/GTzkpL3X</a></p>
  
  <p>This is an excerpt that actually shows the error:</p>
  
  <blockquote>
    <p><strong>Failed install preflight: Error Domain=PKInstallErrorDomain Code=102 "The package “DeveloperTools.pkg” is untrusted." UserInfo=0x7f9d5da29060 {NSLocalizedDescription=The package “DeveloperTools.pkg” is untrusted., NSURL=../Packages/DeveloperTools.pkg -- file://localhost/Applications/Install%20Xcode.app/Contents/Resources/Xcode.mpkg/, PKInstallPackageIdentifier=com.apple.pkg.DeveloperToolsLeo, NSUnderlyingError=0x7f9d5d9eab40 "The operation couldn’t be completed. CSSMERR_TP_CERT_EXPIRED"}</strong>  </p>
  </blockquote>