diff --git a/src/DPD/pair_dpd.cpp b/src/DPD/pair_dpd.cpp
index c1602a69b1b9de63792e83816e19759f533208db..7bea9574ccdba6084310eef785f238e37d6dedd6 100644
--- a/src/DPD/pair_dpd.cpp
+++ b/src/DPD/pair_dpd.cpp
@@ -202,8 +202,7 @@ void PairDPD::settings(int narg, char **arg)
 
   // initialize Marsaglia RNG with processor-unique seed
 
-  if (seed <= 0 || seed > 900000000)
-    error->all("Illegal fix pair_style command");
+  if (seed <= 0) error->all("Illegal fix pair_style command");
   if (random) delete random;
   random = new RanMars(lmp,seed + comm->me);
 
diff --git a/src/GRANULAR/fix_pour.cpp b/src/GRANULAR/fix_pour.cpp
index a392c5b6a8562ba4c1d175fa275fae7a8301144c..c580123c536514a8fb40af54175e70b1f6f48fb1 100644
--- a/src/GRANULAR/fix_pour.cpp
+++ b/src/GRANULAR/fix_pour.cpp
@@ -51,6 +51,8 @@ FixPour::FixPour(LAMMPS *lmp, int narg, char **arg) :
   ntype = atoi(arg[4]);
   seed = atoi(arg[5]);
 
+  if (seed <= 0) error->all("Illegal fix pour command");
+
   PI = 4.0*atan(1.0);
 
   // option defaults
diff --git a/src/displace_atoms.cpp b/src/displace_atoms.cpp
index 6bb5ffab994b623cf2fe11e8ddc4b021909aac24..ab32959e80e8e84089def5dbc16088300c7e988e 100644
--- a/src/displace_atoms.cpp
+++ b/src/displace_atoms.cpp
@@ -175,6 +175,7 @@ void DisplaceAtoms::command(int narg, char **arg)
     double dy = yscale*atof(arg[3]);
     double dz = zscale*atof(arg[4]);
     int seed = atoi(arg[5]);
+    if (seed <= 0) error->all("Illegal displace_atoms random command");
 
     double **x = atom->x;
     int *mask = atom->mask;
diff --git a/src/fix_deposit.cpp b/src/fix_deposit.cpp
index 24d1ec23880986ccb9d55c5ae1f301000f5c764b..fbaa5f4b81a9b4fa59364b7b743b5ccf6bbf8994 100644
--- a/src/fix_deposit.cpp
+++ b/src/fix_deposit.cpp
@@ -43,6 +43,8 @@ FixDeposit::FixDeposit(LAMMPS *lmp, int narg, char **arg) :
   nfreq = atoi(arg[5]);
   seed = atoi(arg[6]);
 
+  if (seed <= 0) error->all("Illegal fix deposit command");
+
   // set defaults
 
   iregion = -1;
diff --git a/src/fix_indent.h b/src/fix_indent.h
index f64b5bf62ed02bcd80dff020fdeae4d7b32730e5..f0604146da9b92bd2be7ef626a338db73c61677b 100644
--- a/src/fix_indent.h
+++ b/src/fix_indent.h
@@ -25,13 +25,13 @@ class FixIndent : public Fix {
   void init();
   void setup();
   void min_setup();
-  void post_force(int);
+  virtual void post_force(int);
   void post_force_respa(int, int, int);
   void min_post_force(int);
   double compute_scalar();
   double compute_vector(int);
 
- private:
+ protected:
   int istyle,scaleflag,radflag,thermo_flag,eflag_enable;
   double k,k3;
   double x0,y0,z0,r0_stop,r0_start;
diff --git a/src/fix_langevin.cpp b/src/fix_langevin.cpp
index 4753845af7e10367784e18e681429f7c2daff083..7fb556639e6bc99bf1af51ff2daac7519ac12e48 100644
--- a/src/fix_langevin.cpp
+++ b/src/fix_langevin.cpp
@@ -41,8 +41,7 @@ FixLangevin::FixLangevin(LAMMPS *lmp, int narg, char **arg) :
   int seed = atoi(arg[6]);
 
   if (t_period <= 0.0) error->all("Fix langevin period must be > 0.0");
-  if (seed <= 0 || seed > 900000000)
-    error->all("Illegal fix langevin command");
+  if (seed <= 0) error->all("Illegal fix langevin command");
 
   // initialize Marsaglia RNG with processor-unique seed
 
diff --git a/src/random_park.cpp b/src/random_park.cpp
index 47c408e7fabcc1e5aa1c94e706402d9443773526..0c01d1eb8c1ed53dfea06422acff291a83dc9a8e 100644
--- a/src/random_park.cpp
+++ b/src/random_park.cpp
@@ -40,7 +40,7 @@ using namespace LAMMPS_NS;
 
 RanPark::RanPark(LAMMPS *lmp, int seed_init) : Pointers(lmp)
 {
-  if (seed_init == 0) error->all("Invalid seed for Park random # generator");
+  if (seed_init <= 0) error->all("Invalid seed for Park random # generator");
   seed = seed_init;
   save = 0;
 }
diff --git a/src/velocity.cpp b/src/velocity.cpp
index 138891fc309650f411199112a130b8210aa5a17a..8747dcebaeec0837258f49ebbc0a40f7e6402906 100644
--- a/src/velocity.cpp
+++ b/src/velocity.cpp
@@ -126,6 +126,8 @@ void Velocity::create(int narg, char **arg)
   double t_desired = atof(arg[0]);
   int seed = atoi(arg[1]);
 
+  if (seed <= 0) error->all("Illegal velocity create command");
+
   // if temperature = NULL, create a new ComputeTemp with the velocity group
 
   int tflag = 0;