Hi! The openmp variant should be deleted from the Portfile which I am just using to compile graph-tool. The apple gcc does not like openmp and prefers to crash instead of properly compiling... So forget about my previous post. CU, -- Sebastian Weber Group of Cell Communication and Control Freiburg Institute for Advanced Studies - FRIAS School of Life Sciences - LIFENET Albert-Ludwigs-Universität Freiburg Albertstr. 19 79104 Freiburg T.: +49-761-203-97237 Fax:+49-761-203-97334