Hi, I'm trying to install the package 'nloptr' and am getting the error configure: error: in `/scratch/tmp/RtmpJ2Y1xA/R.INSTALL3b35583b483/nloptr': configure: error: C++ preprocessor "/lib/cpp" fails sanity check See `config.log' for more details I would like to check 'config.log', but the install directory is automatically deleted. I seem to remember there being an option to 'install.packages' which prevented the temporary build directory from being deleted, but with R version 3.2.3 I can't find it. I've tried setting 'destdir' and 'clean=FALSE', but neither helps. Is there such an option? If so, what is it? If not, how can I preserve 'config.log'? Cheers, Loris -- Dr. Loris Bennett (Mr.) ZEDAT, Freie Universit?t Berlin Email loris.bennett at fu-berlin.de