title: R Download.File Issue with Excel Workbook
body: <p>I'm trying to download an Excel workbook using R's <a href="http://stat.ethz.ch/R-manual/R-patched/library/utils/html/download.file.html" rel="noreferrer">download.file</a> function.</p>
  
  <p>When I download the file manually (using Internet Explorer or Chrome, right click &amp; save as) then the file downloads and I can then open it in Excel without any problems.</p>
  
  <p>When I use download.file in R, the file downloads and reports the correct file size. However when I then try to open the downloaded xls file in Excel 2010 I get the following error message:</p>
  
  <blockquote>
    <p>Excel found unreadable content in 'test.xls'. Do you want to recover the contents of this workbook? If you trust the source of this workbook, click Yes.</p>
  </blockquote>
  
  <p>When I click Yes, nothing happens.</p>
  
  <p>I've also tried accessing the file directly using the R package <a href="http://cran.r-project.org/web/packages/xlsx/index.html" rel="noreferrer">xlsx</a>, this also fails.</p>