Hi, I am facing an error when building MPICH 3.1.1 release with per-object critical sections enabled. I am getting the following errors related to multiple definition of "MPIU_Thread_CS_enter_lockname_impl_" : ..... GEN lib/libmpi.la src/mpi/attr/.libs/lib_libmpi_la-comm_delete_attr.o: In function `MPIU_Thread_CS_enter_lockname_impl_': src/mpi/attr/comm_delete_attr.c:(.text+0x530): multiple definition of `MPIU_Thread_CS_enter_lockname_impl_' src/mpi/attr/.libs/lib_libmpi_la-comm_create_keyval.o:src/mpi/attr/comm_create_keyval.c:(.text+0x290): first defined here src/mpi/attr/.libs/lib_libmpi_la-comm_delete_attr.o: In function `MPIU_Thread_CS_exit_lockname_impl_': src/mpi/attr/comm_delete_attr.c:(.text+0x570): multiple definition of `MPIU_Thread_CS_exit_lockname_impl_' src/mpi/attr/.libs/lib_libmpi_la-comm_create_keyval.o:src/mpi/attr/comm_create_keyval.c:(.text+0x2d0): first defined here ..... This is the configure line: ./configure --disable-fortran --disable-cxx --enable-thread-cs=per-object I am testing on x86_64 linux desktop with Intel compilers and device/channel: ch3/nemesis. Is there a quick fix to this issue? Regards, Halim