title: Migration from XCode3 to 4 Issue with Build
body: <p>Have a existing project on XCode 3 and since it could not simulate iOS5 decided to move to XCode 4. Installed Xcode 4 and to do that i had to upgrade to Mac OS 10.6.8
  Imported the existing project to Xcode 4 and i have issues with the build</p>
  
  <p>Following is the  error i get :</p>
  
  <p>error: remove /Users/UK/Downloads/XYZ/DerivedData/XYZ/Build/Products/Debug-iphonesimulator/XYZ.app/XYZ.app: Directory not empty</p>
  
  <p>I have tried the following options :</p>
  
  <ol>
  <li>From the Organizer in XCode 4 tried to clean the Derived Data by deleting it.</li>
  <li>Gone to the folder where Derived Data is and deleted it physically.</li>
  </ol>
  
  <p>I still get the same build issue. </p>