title: package is in use and will not be installed
body: <p>Using R x64 3.2.3 I get this message:</p>
  
  <pre><code>&gt; install.packages("stringr")
  Installing package into ‘C:/Users/leews/Documents/R/win-library/3.2’
  (as ‘lib’ is unspecified)
  Error: package ‘stringr’ is in use and will not be installed
  </code></pre>
  
  <p>what I have to do??</p>