diff --git a/plugins/Full_CI_ZMQ/fci_zmq.irp.f b/plugins/Full_CI_ZMQ/fci_zmq.irp.f
index 91adeea0..03989552 100644
--- a/plugins/Full_CI_ZMQ/fci_zmq.irp.f
+++ b/plugins/Full_CI_ZMQ/fci_zmq.irp.f
@@ -21,8 +21,10 @@ program fci_zmq
   threshold_davidson = threshold_davidson_in * 100.d0
   SOFT_TOUCH threshold_davidson
 
-  call diagonalize_CI
-  call save_wavefunction
+  if (N_det < N_states) then
+    call diagonalize_CI
+    call save_wavefunction
+  endif
   
   call ezfio_has_hartree_fock_energy(has)
   if (has) then