Dear mpich.org<http://mpich.org>, I was able to compile with gcc 10.2.0. Thank you, Doug. On Dec 29, 2021, at 9:40 AM, Douglas G Dommermuth <[email protected]<mailto:[email protected]>> wrote: Dear mpich.org<http://mpich.org/>, I apologize. I sent this email out with the wrong subject matter. Here is the correct subject. Thank you. I am getting an error installing mpich-3.4.3 on a MacBook Air (M1,2020) with macOS Monterey 12.1, gcc 11.2.0, g++ 11.2.0, and gfortran 11.2.0. I used the following commands: ./configure FFLAGS=-fallow-argument-mismatch --prefix=/Users/douglasdommermuth/mpich2/mpich2-install | & tee c.txt make clean make V=1 | & tee m.txt I get the following error: CC src/mpi/attr/lib_libpmpi_la-attr_delete.lo In file included from ./src/mpid/ch4/netmod/include/../ofi/ofi_impl.h:10, from ./src/mpid/ch4/netmod/include/../ofi/ofi_am.h:8, from ./src/mpid/ch4/netmod/include/../ofi/netmod_inline.h:9, from ./src/mpid/ch4/netmod/include/netmod_impl.h:1644, from ./src/mpid/ch4/include/mpidch4.h:322, from ./src/mpid/ch4/include/mpidpost.h:10, from ./src/include/mpiimpl.h:241, from src/mpi/attr/attr_delete.c:6: ./src/mpid/ch4/netmod/include/../ofi/ofi_types.h:326:5: error: size of array element is not a multiple of its alignment 326 | MPIDI_OFI_cacheline_mutex_t mutexes[MAX_OFI_MUTEXES]; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ make[2]: *** [src/mpi/attr/lib_libpmpi_la-attr_delete.lo] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 An online search indicates that others are experiencing this error with gcc 11. For example, here https://github.com/JayDDee/cpuminer-opt/issues/313, https://gitlab.com/xonotic/darkplaces/-/issues/363, and https://github.com/relic-toolkit/relic/issues/202. I have not tried an earlier version of gcc. Compressed versions of c.txt, m.txt, and config log files are attached. Thank you, Doug. <m.txt.gz><c.txt.gz><config.log.gz><src_pm_hydra_config.log.gz><src_mpl_config.log.gz>