title: Causes of "Error: package '_____' was built before 3.0.0: please re-install it" in R
body: <p>On one computer running R 2.15.2 I have installed packages from a .zip file (these packages happened to be <em>ggplot2</em> and <em>data.table</em>, but I don't think the specific package is my issue.) Everything works fine. I took these packages to a computer without an internet connection and installed them. This other computer is running R 3.0.1. The packages seemed to install without a problem (using R's "install package(s) from local zip file" option). When I call the packages with the <em>library()</em>, I get the following error:</p>
  
  <pre><code>Error: package '&lt;insert name of newly installed package here&gt;' was build before 3.0.0: please-re-install it
  </code></pre>
  
  <p>Can anyone explain potential causes for this error to be thrown? Are there particular directories that the .zip packages must be in for a proper install? If R is installed on a separate partition from where the .zip packages were loaded, could this cause the error? </p>
  
  <p>I'm at a loss, any pointers are greatly appreciated. This is a difficult one to reproduce; if you need any other version/system parameters to understand the problem, please don't hesitate to ask.</p>