diff --git a/plugins/MRCC_Utils/amplitudes.irp.f b/plugins/MRCC_Utils/amplitudes.irp.f
index b38402a2..0e6a4cf4 100644
--- a/plugins/MRCC_Utils/amplitudes.irp.f
+++ b/plugins/MRCC_Utils/amplitudes.irp.f
@@ -66,9 +66,18 @@
 
 END_PROVIDER
 
+BEGIN_PROVIDER [ integer, n_exc_active_sze ]
+ implicit none
+ BEGIN_DOC
+ ! Dimension of arrays to avoid zero-sized arrays
+ END_DOC
+ n_exc_active_sze = max(n_exc_active,1)
+END_PROVIDER
 
- BEGIN_PROVIDER [ integer, active_excitation_to_determinants_idx, (0:N_det_ref+1, n_exc_active) ]
-&BEGIN_PROVIDER [ double precision, active_excitation_to_determinants_val, (N_states,N_det_ref+1, n_exc_active) ]
+
+
+ BEGIN_PROVIDER [ integer, active_excitation_to_determinants_idx, (0:N_det_ref+1, n_exc_active_sze) ]
+&BEGIN_PROVIDER [ double precision, active_excitation_to_determinants_val, (N_states,N_det_ref+1, n_exc_active_sze) ]
  implicit none
  BEGIN_DOC
  ! Sparse matrix A containing the matrix to transform the active excitations to
@@ -136,10 +145,10 @@ END_PROVIDER
 END_PROVIDER
 
 
- BEGIN_PROVIDER [ integer, mrcc_AtA_ind, (N_det_ref * n_exc_active) ]
-&BEGIN_PROVIDER [ double precision, mrcc_AtA_val, (N_states, N_det_ref * n_exc_active) ]
-&BEGIN_PROVIDER [ integer, mrcc_col_shortcut, (n_exc_active) ]
-&BEGIN_PROVIDER [ integer, mrcc_N_col, (n_exc_active) ]
+ BEGIN_PROVIDER [ integer, mrcc_AtA_ind, (N_det_ref * n_exc_active_sze) ]
+&BEGIN_PROVIDER [ double precision, mrcc_AtA_val, (N_states, N_det_ref * n_exc_active_sze) ]
+&BEGIN_PROVIDER [ integer, mrcc_col_shortcut, (n_exc_active_sze) ]
+&BEGIN_PROVIDER [ integer, mrcc_N_col, (n_exc_active_sze) ]
  implicit none
  BEGIN_DOC
  ! A is active_excitation_to_determinants in At.A
diff --git a/plugins/MRCC_Utils/davidson.irp.f b/plugins/MRCC_Utils/davidson.irp.f
index 2c9f5f03..978c96cb 100644
--- a/plugins/MRCC_Utils/davidson.irp.f
+++ b/plugins/MRCC_Utils/davidson.irp.f
@@ -829,7 +829,9 @@ subroutine davidson_diag_hjj_sjj_mrcc(dets_in,u_in,H_jj,S2_jj,energies,dim_in,sz
             state_ok(k) = (dabs(s2(k)-expected_s2) < 0.6d0)
           enddo
       else
-        state_ok(k) = .True.
+        do k=1,size(state_ok)
+          state_ok(k) = .True.
+        enddo
       endif
 
       do k=1,shift2
diff --git a/src/Davidson/diagonalization_hs2.irp.f b/src/Davidson/diagonalization_hs2.irp.f
index 2402f973..5b5edbbf 100644
--- a/src/Davidson/diagonalization_hs2.irp.f
+++ b/src/Davidson/diagonalization_hs2.irp.f
@@ -306,7 +306,9 @@ subroutine davidson_diag_hjj_sjj(dets_in,u_in,H_jj,S2_jj,energies,dim_in,sze,N_s
             state_ok(k) = (dabs(s2(k)-expected_s2) < 0.6d0)
           enddo
       else
-        state_ok(k) = .True.
+        do k=1,size(state_ok)
+          state_ok(k) = .True.
+        enddo
       endif
 
       do k=1,shift2
@@ -385,7 +387,8 @@ subroutine davidson_diag_hjj_sjj(dets_in,u_in,H_jj,S2_jj,energies,dim_in,sze,N_s
       do k=1,N_st_diag
         if (state_ok(k)) then
           do i=1,sze
-            U(i,shift2+k) = (lambda(k) * U(i,shift2+k) - W(i,shift2+k) )      &
+            U(i,shift2+k) =  &
+              (lambda(k) * U(i,shift2+k) - W(i,shift2+k) )      &
                 * (1.d0 + s2(k) * U(i,shift2+k) - S(i,shift2+k) - S_z2_Sz &
               )/max(H_jj(i) - lambda (k),1.d-2)
           enddo