title: Mercurial suddenly thinks all files have changed - waiting for lock on working directory
body: <p>I've been using Mercurial v 1.1 for several months to version documents and other files.  Yesterday it suddenly failed with the message:</p>
  
  <pre><code>waiting for lock on working directory
  </code></pre>
  
  <p>This happens in all projects I have under .hg control.  Mercurial also thinks that all files in all projects have changed.</p>
  
  <p>There is no .hg/store/lock file in the project it says it is waiting on the lock for.</p>
  
  <p>The only thing that could have caused this is that Windows installed security patch on my computer overnight.</p>
  
  <p>Has anyone else seen this with Mercurial?</p>