diff --git a/src/MOLECULE/dihedral_harmonic.cpp b/src/MOLECULE/dihedral_harmonic.cpp
index f1e5811a84..4f6a88eca5 100644
--- a/src/MOLECULE/dihedral_harmonic.cpp
+++ b/src/MOLECULE/dihedral_harmonic.cpp
@@ -42,7 +42,7 @@ DihedralHarmonic::DihedralHarmonic(LAMMPS *lmp) : Dihedral(lmp)
 
 DihedralHarmonic::~DihedralHarmonic()
 {
-  if (allocated) {
+  if (allocated && !copymode) {
     memory->destroy(setflag);
     memory->destroy(k);
     memory->destroy(sign);
diff --git a/src/MOLECULE/dihedral_harmonic.h b/src/MOLECULE/dihedral_harmonic.h
index 938e59918b..6792d16a20 100644
--- a/src/MOLECULE/dihedral_harmonic.h
+++ b/src/MOLECULE/dihedral_harmonic.h
@@ -29,16 +29,16 @@ class DihedralHarmonic : public Dihedral {
   DihedralHarmonic(class LAMMPS *);
   virtual ~DihedralHarmonic();
   virtual void compute(int, int);
-  void coeff(int, char **);
+  virtual void coeff(int, char **);
   void write_restart(FILE *);
-  void read_restart(FILE *);
+  virtual void read_restart(FILE *);
   void write_data(FILE *);
 
  protected:
   double *k,*cos_shift,*sin_shift;
   int *sign,*multiplicity;
 
-  void allocate();
+  virtual void allocate();
 };
 
 }