Hello, I am having trouble compiling a F90 code using mpif90. I get the following error: ld: library not found for -lSystemStubs I am running Mac OS X 10.7.5, which is highest OS that I can put on my Mac Pro Dual-Core Intel Xeon. I am using intel icc version 13.0.1 and intel ifort version 13.0.1. I am using Xcode version 4.6. I am using MPICH 3.0.2. Here are the first few lines of c.txt: Configuring MPICH version 3.0.2 with '--prefix=/Users/dougdommermuth/mpich2/mpich-install' 'CC=/usr/bin/icc' 'FC=/usr/bin/ifort' Running on system: Darwin Macintosh-2.local 11.4.2 Darwin Kernel Version 11.4.2: Thu Aug 23 16:26:45 PDT 2012; root:xnu-1699.32.7~1/RELEASE_I386 i386 checking whether the C compiler works... yes Any suggestions on how to fix this problem? Thank you, Doug.