diff --git a/src/DPD-REACT/fix_shardlow.cpp b/src/DPD-REACT/fix_shardlow.cpp
index 65fa14daeb..955f1ddd0a 100644
--- a/src/DPD-REACT/fix_shardlow.cpp
+++ b/src/DPD-REACT/fix_shardlow.cpp
@@ -549,12 +549,9 @@ void FixShardlow::initial_integrate(int /*vflag*/)
     error->all(FLERR,"Fix shardlow does not yet support triclinic geometries");
 
   if (rcut >= bbx || rcut >= bby || rcut>= bbz )
-  {
-    char fmt[] = {"Shardlow algorithm requires sub-domain length > 2*(rcut+skin). Either reduce the number of processors requested, or change the cutoff/skin: rcut= %e bbx= %e bby= %e bbz= %e\n"};
-    char *msg = (char *) malloc(sizeof(fmt) + 4*15);
-    sprintf(msg, fmt, rcut, bbx, bby, bbz);
-    error->one(FLERR, msg);
-  }
+    error->one(FLERR,"Shardlow algorithm requires sub-domain length > 2*(rcut+skin). "
+                    "Either reduce the number of processors requested, or change the cutoff/skin: "
+                    "rcut= {} bbx= {} bby= {} bbz= {}\n", rcut, bbx, bby, bbz);
 
   NPairHalfBinNewtonSSA *np_ssa = dynamic_cast<NPairHalfBinNewtonSSA*>(list->np);
   if (!np_ssa) error->one(FLERR, "NPair wasn't a NPairHalfBinNewtonSSA object");
diff --git a/src/REPLICA/fix_pimd.cpp b/src/REPLICA/fix_pimd.cpp
index bb4af16f1b..d4b3447f15 100644
--- a/src/REPLICA/fix_pimd.cpp
+++ b/src/REPLICA/fix_pimd.cpp
@@ -676,16 +676,11 @@ void FixPIMD::comm_exec(double **ptr)
       int index = atom->map(tag_send[i]);
 
       if (index < 0) {
-        char error_line[256];
-
-        sprintf(error_line,
-                "Atom " TAGINT_FORMAT " is missing at world [%d] "
-                "rank [%d] required by  rank [%d] (" TAGINT_FORMAT ", " TAGINT_FORMAT
-                ", " TAGINT_FORMAT ").\n",
-                tag_send[i], universe->iworld, comm->me, plan_recv[iplan], atom->tag[0],
-                atom->tag[1], atom->tag[2]);
-
-        error->universe_one(FLERR, error_line);
+        auto mesg = fmt::format("Atom {} is missing at world [{}] rank [{}] "
+                                "required by rank [{}] ({}, {}, {}).\n",
+                                tag_send[i], universe->iworld, comm->me,
+                                plan_recv[iplan], atom->tag[0], atom->tag[1], atom->tag[2]);
+        error->universe_one(FLERR, mesg);
       }
 
       memcpy(wrap_ptr, ptr[index], ncpy);
diff --git a/src/REPLICA/tad.cpp b/src/REPLICA/tad.cpp
index 881ec1604c..0b1cc915c6 100644
--- a/src/REPLICA/tad.cpp
+++ b/src/REPLICA/tad.cpp
@@ -840,11 +840,9 @@ void TAD::initialize_event_list() {
 
 void TAD::delete_event_list() {
 
-  for (int i = 0; i < n_event_list; i++) {
-    char str[128];
-    sprintf(str,"tad_event_%d",i);
-    modify->delete_fix(str);
-  }
+  for (int i = 0; i < n_event_list; i++)
+    modify->delete_fix(fmt::format("tad_event_{}",i));
+
   memory->sfree(fix_event_list);
   fix_event_list = nullptr;
   n_event_list = 0;