diff --git a/src/balance.cpp b/src/balance.cpp
index 03ee4a8195..af142f404d 100644
--- a/src/balance.cpp
+++ b/src/balance.cpp
@@ -458,7 +458,7 @@ void Balance::options(int iarg, int narg, char **arg)
         nopt = imb->options(narg-iarg,arg+iarg+2);
         imbalances[nimbalance++] = imb;
       } else {
-        error->all(FLERR,"Unknown (fix) balance weight method");
+        error->all(FLERR,"Unknown (fix) balance weight method: {}", arg[iarg+1]);
       }
       iarg += 2+nopt;
 
diff --git a/src/imbalance_group.cpp b/src/imbalance_group.cpp
index f4c883ff4c..e674338e76 100644
--- a/src/imbalance_group.cpp
+++ b/src/imbalance_group.cpp
@@ -48,7 +48,7 @@ int ImbalanceGroup::options(int narg, char **arg)
   for (int i = 0; i < num; ++i) {
     id[i] = group->find(arg[2*i+1]);
     if (id[i] < 0)
-      error->all(FLERR,"Unknown group in balance weight command");
+      error->all(FLERR,"Unknown group in balance weight command: {}", arg[2*i+1]);
     factor[i] = utils::numeric(FLERR,arg[2*i+2],false,lmp);
     if (factor[i] <= 0.0) error->all(FLERR,"Illegal balance weight command");
   }
diff --git a/src/info.cpp b/src/info.cpp
index 12546b6be9..049bdd5bfd 100644
--- a/src/info.cpp
+++ b/src/info.cpp
@@ -814,13 +814,13 @@ bool Info::is_active(const char *category, const char *name)
       return (lmp->kokkos && lmp->kokkos->kokkos_exists) ? true : false;
     } else if (strcmp(name,"omp") == 0) {
       return (modify->find_fix("package_omp") >= 0) ? true : false;
-    } else error->all(FLERR,"Unknown name for info package category");
+    } else error->all(FLERR,"Unknown name for info package category: {}", name);
 
   } else if (strcmp(category,"newton") == 0) {
     if (strcmp(name,"pair") == 0) return (force->newton_pair != 0);
     else if (strcmp(name,"bond") == 0) return (force->newton_bond != 0);
     else if (strcmp(name,"any") == 0) return (force->newton != 0);
-    else error->all(FLERR,"Unknown name for info newton category");
+    else error->all(FLERR,"Unknown name for info newton category: {}", name);
 
   } else if (strcmp(category,"pair") == 0) {
     if (force->pair == nullptr) return false;
@@ -829,7 +829,7 @@ bool Info::is_active(const char *category, const char *name)
     else if (strcmp(name,"manybody") == 0) return (force->pair->manybody_flag != 0);
     else if (strcmp(name,"tail") == 0) return (force->pair->tail_flag != 0);
     else if (strcmp(name,"shift") == 0) return (force->pair->offset_flag != 0);
-    else error->all(FLERR,"Unknown name for info pair category");
+    else error->all(FLERR,"Unknown name for info pair category: {}", name);
 
   } else if (strcmp(category,"comm_style") == 0) {
     style = commstyles[comm->style];
@@ -851,7 +851,7 @@ bool Info::is_active(const char *category, const char *name)
     style = force->improper_style;
   } else if (strcmp(category,"kspace_style") == 0) {
     style = force->kspace_style;
-  } else error->all(FLERR,"Unknown category for info is_active()");
+  } else error->all(FLERR,"Unknown category for info is_active(): {}", category);
 
   int match = 0;
   if (strcmp(style,name) == 0) match = 1;
@@ -893,7 +893,7 @@ bool Info::is_available(const char *category, const char *name)
     } else if (strcmp(name,"exceptions") == 0) {
       return has_exceptions();
     }
-  } else error->all(FLERR,"Unknown category for info is_available()");
+  } else error->all(FLERR,"Unknown category for info is_available(): {}", category);
 
   return false;
 }
@@ -952,7 +952,7 @@ bool Info::is_defined(const char *category, const char *name)
       if (strcmp(names[i],name) == 0)
         return true;
     }
-  } else error->all(FLERR,"Unknown category for info is_defined()");
+  } else error->all(FLERR,"Unknown category for info is_defined(): {}", category);
 
   return false;
 }
diff --git a/src/pair_hybrid.cpp b/src/pair_hybrid.cpp
index c2bc37e931..ab2fe7803a 100644
--- a/src/pair_hybrid.cpp
+++ b/src/pair_hybrid.cpp
@@ -494,7 +494,7 @@ void PairHybrid::coeff(int narg, char **arg)
   int none = 0;
   if (m == nstyles) {
     if (strcmp(arg[2],"none") == 0) none = 1;
-    else error->all(FLERR,"Pair coeff for hybrid has invalid style");
+    else error->all(FLERR,"Pair coeff for hybrid has invalid style: {}",arg[2]);
   }
 
   // move 1st/2nd args to 2nd/3rd args
@@ -896,7 +896,7 @@ void PairHybrid::modify_params(int narg, char **arg)
     int m;
     for (m = 0; m < nstyles; m++)
       if (strcmp(arg[1],keywords[m]) == 0) break;
-    if (m == nstyles) error->all(FLERR,"Unknown pair_modify hybrid sub-style");
+    if (m == nstyles) error->all(FLERR,"Unknown pair_modify hybrid sub-style: {}",arg[1]);
     int iarg = 2;
 
     if (multiple[m]) {
@@ -905,7 +905,7 @@ void PairHybrid::modify_params(int narg, char **arg)
       for (m = 0; m < nstyles; m++)
         if (strcmp(arg[1],keywords[m]) == 0 && multiflag == multiple[m]) break;
       if (m == nstyles)
-        error->all(FLERR,"Unknown pair_modify hybrid sub-style");
+        error->all(FLERR,"Unknown pair_modify hybrid sub-style: {}",arg[1]);
       iarg = 3;
     }
 
diff --git a/src/pair_table.cpp b/src/pair_table.cpp
index ee3a6454c9..f064d56377 100644
--- a/src/pair_table.cpp
+++ b/src/pair_table.cpp
@@ -215,7 +215,7 @@ void PairTable::settings(int narg, char **arg)
   else if (strcmp(arg[0],"linear") == 0) tabstyle = LINEAR;
   else if (strcmp(arg[0],"spline") == 0) tabstyle = SPLINE;
   else if (strcmp(arg[0],"bitmap") == 0) tabstyle = BITMAP;
-  else error->all(FLERR,"Unknown table style in pair_style command");
+  else error->all(FLERR,"Unknown table style in pair_style command: {}", arg[0]);
 
   tablength = utils::inumeric(FLERR,arg[1],false,lmp);
   if (tablength < 2) error->all(FLERR,"Illegal number of pair table entries");
diff --git a/src/thermo.cpp b/src/thermo.cpp
index f030ac2391..1fa6f18d2c 100644
--- a/src/thermo.cpp
+++ b/src/thermo.cpp
@@ -908,7 +908,7 @@ void Thermo::parse_fields(char *str)
       if ((argi.get_type() == ArgInfo::UNKNOWN)
           || (argi.get_type() == ArgInfo::NONE)
           || (argi.get_dim() > 2))
-        error->all(FLERR,"Unknown keyword in thermo_style custom command");
+        error->all(FLERR,"Unknown keyword '{}' in thermo_style custom command",word);
 
       // process zero or one or two trailing brackets
       // argindex1,argindex2 = int inside each bracket pair, 0 if no bracket