diff --git a/src/grid_mod.F90 b/src/grid_mod.F90
index 1e98b6c1e2e177b9ea0984e322cb1dd0c5f70c4f..06e47107275bd6b75900abb8f7aa833d8f8b7d39 100644
--- a/src/grid_mod.F90
+++ b/src/grid_mod.F90
@@ -517,6 +517,7 @@ CONTAINS
       IF(zarray_full(iz) .LT. zmin) zmin = zarray_full(iz)
     END DO
     !! Parallel data distribution
+    IF( num_procs_z .GT. 1) stop '>>STOPPED<< Cannot have multiple core in z-direction (Nz = 1)'
     ! Local data distribution
     CALL decomp1D(total_nz, num_procs_z, rank_z, izs, ize)
     local_nz = ize - izs + 1