title: New Rmd document: knitr: Error in library("rstudio") : there is no package called 'rstudio'
body: <p>firing up "RStudio" V1.0.136 on my Mac, just as usual, creating a new file, a Rmd, and trying--as I've done countless time before--knitr it just as is, but this time a strange error message occurs:</p>
  
  <pre><code>Error in library("rstudio") : there is no package called 'rstudio'
  </code></pre>
  
  <p>Never ever have seen this before, and I haven't got the faintest clue as why this has popped into existence, and how to remedy it.</p>