diff --git a/src/COLVARS/group_ndx.cpp b/src/COLVARS/group_ndx.cpp
index a45c0c1bf0..0e9da8cce3 100644
--- a/src/COLVARS/group_ndx.cpp
+++ b/src/COLVARS/group_ndx.cpp
@@ -47,7 +47,7 @@ static int cmptagint(const void *p1, const void *p2)
 
 void Group2Ndx::command(int narg, char **arg)
 {
-  FILE *fp;
+  FILE *fp = nullptr;
 
   if (narg < 1) error->all(FLERR,"Illegal group2ndx command");
 
@@ -57,8 +57,7 @@ void Group2Ndx::command(int narg, char **arg)
   if (comm->me == 0) {
     fp = fopen(arg[0], "w");
     if (fp == nullptr)
-      error->one(FLERR,"Cannot open index file for writing: {}",
-                                   utils::getsyserror());
+      error->one(FLERR,"Cannot open index file for writing: {}", utils::getsyserror());
     utils::logmesg(lmp,"Writing groups to index file {}:\n",arg[0]);
   }
 
diff --git a/src/EFF/fix_nvt_sllod_eff.cpp b/src/EFF/fix_nvt_sllod_eff.cpp
index 8b7c6bac9b..333c98668c 100644
--- a/src/EFF/fix_nvt_sllod_eff.cpp
+++ b/src/EFF/fix_nvt_sllod_eff.cpp
@@ -51,6 +51,7 @@ FixNVTSllodEff::FixNVTSllodEff(LAMMPS *lmp, int narg, char **arg) :
   modify->add_compute(fmt::format("{} {} tmp/deform/eff",
                                   id_temp,group->names[igroup]));
   tcomputeflag = 1;
+  nondeformbias = 0;
 }
 
 /* ---------------------------------------------------------------------- */