o Added shell.exec2(), which does a better job than shell.exec() in
  opening pathnames with forward slashes and files on mapped drives,
  which may or may not open depending software, e.g. Google Chrome
  fails to open the latter.  Add options(browser=R.utils::shell.exec2)
  to your ~/.Rprofile file to make browseURL() use this function
  instead of shell.exec().  This function is only useful on
  Windows.