title: LyX 2.1.1 fails to compile knitr-manual.lyx
body: <p>LyX 2.1.1 fails to compile <a href="https://github.com/yihui/knitr/blob/master/inst/examples/knitr-manual.lyx" rel="nofollow noreferrer">knitr-manual.lyx</a> and <a href="https://github.com/yihui/knitr/blob/master/inst/examples/knitr-graphics.lyx" rel="nofollow noreferrer">knitr-graphics.lyx</a> as well (currently installed knitr version 1.6).</p>
  
  <p>The error does not say much (i.e. <code>LyX: Cannot convert file</code> -- see screenshot).  Could it be related to file-permission bits?  How should I go about it?</p>
  
  <p><img src="https://i.stack.imgur.com/ELF1Q.png" alt="enter image description here"></p>
  
  <p>Maybe of interest,</p>
  
  <pre><code>Sys.getlocale()
  [1] "LC_CTYPE=en_US.UTF-8;LC_NUMERIC=C;LC_TIME=en_US.UTF-8;LC_COLLATE=C;LC_MONETARY=en_US.UTF-8;LC_MESSAGES=en_US.UTF-8;LC_PAPER=en_US.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US.UTF-8;LC_IDENTIFICATION=C"
  </code></pre>
  
  <p><strong>Update</strong></p>
  
  <p>From the message pane, there is indeed an <em>Error</em> line:</p>
  
  <pre><code>12:28:16.235: Quitting from lines 93-93 (/tmp/lyx_tmpdir.gwIlgToM2017/lyx_tmpbuf1/knitr-graphics.Rnw) 
  12:28:16.238: Error in loadNamespace(name) : there is no package called 'Cairo'
  12:28:16.241: Calls: knit ... tryCatch -&gt; tryCatchList -&gt; tryCatchOne -&gt; &lt;Anonymous&gt;
  12:28:16.244: 
  12:28:16.247: Execution halted
  </code></pre>
  
  <p>No cairo?  What does this mean in the contect of knitr and LyX/LaTeX?</p>