Using the current as of this morning from git, hash 1d340282 , and with CC=gcc-10 (needed to work with the corresponding version of gfortran, because gcc on OSX is really clang) ../../sources/mpich/configure --with-device=ch4:ofi --prefix=/Users/gropp/installs/mpich2-dbg works but make ends with /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: lib/.libs/libmpifort.a(mpi_c_interface_nobuf.o) has no symbols CXX src/binding/cxx/initcxx.lo CXXLD lib/libmpicxx.la<http://libmpicxx.la> CC src/env/mpichversion.o CCLD src/env/mpichversion Undefined symbols for architecture x86_64: "_ofi_process_vm_writev", referenced from: import-atom in libpmpi.dylib ld: symbol(s) not found for architecture x86_64 collect2: error: ld returned 1 exit status make[2]: *** [src/env/mpichversion] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 gropp@wdg-macbook hydra % Configure and make logs attached. (Some of the instructions on the MPICH web page for submitting bug reports sent me to unreachable github web pages) William Gropp Director and Chief Scientist, NCSA Thomas M. Siebel Chair in Computer Science University of Illinois Urbana-Champaign