title: RStudio Server error when restarting the R session
body: <p>This recently began to appear whenever I restart my RStudio Server session:</p>
  
  <pre><code>Error in tools:::httpdPort &gt; 0 : 
    comparison (6) is possible only for atomic and list types
  </code></pre>
  
  <p>It does not seem to relate to running any code (all I do to reproduce it is to go to the Session menu and then click "Restart R"). It appears that we are running version 0.97.551.</p>
  
  <p>What is this error and how can we resolve it?</p>