title: My entire Excel hangs after downloading an Excel from the Internet
body: <p>I am using Office 365 (and have had this problem since moving to Office 365.) </p>
  
  <p>When I load an Excel which has been generated by a web application, then Excel will enter "PROTECTED VIEW"  and will say </p>
  
  <blockquote>
    <p>"Be careful - this file may have come from an unsafe source. Unless
    you need to edit, it's safer to stay in Protected View."</p>
  </blockquote>
  
  <p>and display a button "Enable Editing"</p>
  
  <p>However, this will sometimes freeze my entire Excel, with either no movement whatsoever or extremely sluggish movement (for instance taking 10 seconds to change one cell of a very small workbook)</p>