title: "Error in library(rjson): There is no package called rjson"
body: <p>My rjson package randomly doesn't work.  As in, it works fine sometimes, sometimes it fails to load. Not sure why.</p>
  
  <p>I get this error.</p>
  
  <pre><code>     Error in library("rjson") : there is no package called ‘rjson’
  </code></pre>
  
  <p>To try and alleviate this, despite knowing its installed, I added an install line in my script.</p>
  
  <pre><code>   install.packages("rjson", repos="http://cran.rstudio.com/")
     library(rjson)
  </code></pre>
  
  <p>Now I get....</p>
  
  <p>Installing package(s) into ‘C:/Users/Tom/Documents/R/win-library/2.15’
  (as ‘lib’ is unspecified)
  trying URL '<a href="http://cran.rstudio.com/bin/windows/contrib/2.15/rjson_0.2.13.zip" rel="noreferrer">http://cran.rstudio.com/bin/windows/contrib/2.15/rjson_0.2.13.zip</a>'
  Content type 'application/zip' length 491848 bytes (480 Kb)
  opened URL
  downloaded 480 Kb</p>
  
  <p>package ‘rjson’ successfully unpacked and MD5 sums checked
  Warning: cannot remove prior installation of package ‘rjson’</p>
  
  <p>The downloaded binary packages are in
          C:\Users\Tom\AppData\Local\Temp\RtmpiOfTqK\downloaded_packages</p>
  
  <p>In R, when I go to "Packages --> Load" for some reason rjson is NOT there. It never has been, even when it worked.</p>
  
  <p>I've naviaged to...</p>
  
  <p>C:\Users\Tom\Documents\R\win-library\2.15</p>
  
  <p>I can confirm the folder for rjson is there.  </p>
  
  <p>No idea what to do.</p>