Many thanks to all who replied to this post. the problem has now been sorted out. i installed "GCC-10.7-v2.pkg", now i can install packages from source -- View this message in context: http://r.789695.n4.nabble.com/R-on-mac-not-installing-packages-tp4659392p4659414.html Sent from the R help mailing list archive at Nabble.com.