diff --git a/ompi/runtime/ompi_mpi_params.c b/ompi/runtime/ompi_mpi_params.c
index 7c0b5a48514..21fdaec1217 100644
--- a/ompi/runtime/ompi_mpi_params.c
+++ b/ompi/runtime/ompi_mpi_params.c
@@ -287,7 +287,7 @@ int ompi_mpi_register_params(void)
                                  MCA_BASE_VAR_SCOPE_READONLY,
                                  &ompi_mpi_dynamics_enabled);
 
-    ompi_async_mpi_init = true;
+    ompi_async_mpi_init = false;
     (void) mca_base_var_register("ompi", "async", "mpi", "init",
                                  "Do not perform a barrier at the end of MPI_Init",
                                  MCA_BASE_VAR_TYPE_BOOL, NULL, 0, 0,
diff --git a/opal/mca/pmix/base/pmix_base_frame.c b/opal/mca/pmix/base/pmix_base_frame.c
index b117767d7a1..99d281fe722 100644
--- a/opal/mca/pmix/base/pmix_base_frame.c
+++ b/opal/mca/pmix/base/pmix_base_frame.c
@@ -39,7 +39,7 @@ opal_pmix_base_t opal_pmix_base = {0};
 
 static int opal_pmix_base_frame_register(mca_base_register_flag_t flags)
 {
-    opal_pmix_base_async_modex = true;
+    opal_pmix_base_async_modex = false;
     (void) mca_base_var_register("opal", "pmix", "base", "async_modex", "Use asynchronous modex mode",
                                  MCA_BASE_VAR_TYPE_BOOL, NULL, 0, 0, OPAL_INFO_LVL_9,
                                  MCA_BASE_VAR_SCOPE_READONLY, &opal_pmix_base_async_modex);