title: Why would clicking "View All Site Content" generate an error?
body: <p>I have a SharePoint site where clicking "View All Site Content" generates this error:</p>
  
  <blockquote>
    <p>The URL '/sites/foo/bar' is invalid.  It may refer to a nonexistent file or folder, or refer to a valid file or folder that is not in the current Web.</p>
  </blockquote>
  
  <p>Any ideas?</p>