title: R.java doesn't exist...but it does! Problem started after installing ADT 10.0.0
body: <p>I get this error when I try to clean a project:
  ERROR: Unable to open class file ....R.java: No such file or directory</p>
  
  <p>So I can't build my projects any more.  But R.java is there in the gen folder and looks fine when I open it.</p>
  
  <p>This happens to every one of my projects. I tried completely deleting the Eclipse folder and reinstalling it (Helios on Windows) and Android ADT. No luck.</p>
  
  <p>I have also tried moving my workspace to a different drive. No luck.</p>
  
  <p>I made sure all folders in my workspace are not read only.  This worked the first time, but immediately the error came back when I cleaned my project.</p>
  
  <p>This all started right after installing ADT 10.0.  I am wondering if it somehow is building R.java as a read-only file.</p>
  
  <p>EDIT: Is deleting the eclipse directory sufficient to reset all of its configuration?</p>
  
  <p>More info:  All my projects are fine, until I rebuild or clean them. Then every class that looks at R.java throws an error.</p>