diff --git a/examples/helio_swifter_comparison/swiftest_vs_swifter.ipynb b/examples/helio_swifter_comparison/swiftest_vs_swifter.ipynb
index 7f0b1d4b9..9a4c22cb1 100644
--- a/examples/helio_swifter_comparison/swiftest_vs_swifter.ipynb
+++ b/examples/helio_swifter_comparison/swiftest_vs_swifter.ipynb
@@ -43,9 +43,9 @@
      "output_type": "stream",
      "text": [
       "Reading Swiftest file param.swiftest.in\n",
-      "Reading in time 1.001e+00\n",
+      "Reading in time 1.000e+00\n",
       "Creating Dataset\n",
-      "Successfully converted 1463 output frames.\n",
+      "Successfully converted 1462 output frames.\n",
       "Swiftest simulation data stored as xarray DataSet .ds\n"
      ]
     }
diff --git a/src/rmvs/rmvs_util.f90 b/src/rmvs/rmvs_util.f90
index 8f0d7cf5d..0ba86c7e8 100644
--- a/src/rmvs/rmvs_util.f90
+++ b/src/rmvs/rmvs_util.f90
@@ -27,7 +27,7 @@ module subroutine rmvs_util_append_pl(self, source, lsource_mask)
 
          call whm_util_append_pl(self, source, lsource_mask)
       class default
-         write(*,*) "Invalid object passed to the append method. Source must be of class rmvs_pl or its descendents"
+         write(*,*) "Invalid object passed to the append method. Source must be of class rmvs_pl or its descendents!"
          call util_exit(FAILURE)
       end select
 
@@ -54,7 +54,7 @@ module subroutine rmvs_util_append_tp(self, source, lsource_mask)
 
          call util_append_tp(self, source, lsource_mask)  ! Note: whm_tp does not have its own append method, so we skip back to the base class
       class default
-         write(*,*) "Invalid object passed to the append method. Source must be of class rmvs_tp or its descendents"
+         write(*,*) "Invalid object passed to the append method. Source must be of class rmvs_tp or its descendents!"
          call util_exit(FAILURE)
       end select
 
@@ -91,7 +91,8 @@ module subroutine rmvs_util_fill_pl(self, inserts, lfill_list)
 
             call whm_util_fill_pl(keeps, inserts, lfill_list)
          class default
-            write(*,*) 'Error! spill method called for incompatible return type on rmvs_pl'
+            write(*,*) "Invalid object passed to the fill method. Source must be of class rmvs_pl or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate
 
@@ -120,7 +121,8 @@ module subroutine rmvs_util_fill_tp(self, inserts, lfill_list)
             
             call util_fill_tp(keeps, inserts, lfill_list) ! Note: whm_tp does not have its own fill method, so we skip back to the base class
          class default
-            write(*,*) 'Error! fill method called for incompatible return type on rmvs_tp'
+            write(*,*) "Invalid object passed to the fill method. Source must be of class rmvs_tp or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate
 
@@ -334,7 +336,8 @@ module subroutine rmvs_util_spill_pl(self, discards, lspill_list, ldestructive)
 
             call whm_util_spill_pl(keeps, discards, lspill_list, ldestructive)
          class default
-            write(*,*) 'Error! spill method called for incompatible return type on rmvs_pl'
+            write(*,*) "Invalid object passed to the spill method. Source must be of class rmvs_pl or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate
 
@@ -366,7 +369,8 @@ module subroutine rmvs_util_spill_tp(self, discards, lspill_list, ldestructive)
 
             call util_spill_tp(keeps, discards, lspill_list, ldestructive)
          class default
-            write(*,*) 'Error! spill method called for incompatible return type on rmvs_tp'
+            write(*,*) "Invalid object passed to the spill method. Source must be of class rmvs_tp or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate
 
diff --git a/src/symba/symba_util.f90 b/src/symba/symba_util.f90
index 02d839bb2..4c4b74476 100644
--- a/src/symba/symba_util.f90
+++ b/src/symba/symba_util.f90
@@ -104,7 +104,7 @@ module subroutine symba_util_append_pl(self, source, lsource_mask)
 
          call util_append_pl(self, source, lsource_mask) ! Note: helio_pl does not have its own append method, so we skip back to the base class
       class default
-         write(*,*) "Invalid object passed to the append method. Source must be of class symba_pl or its descendents"
+         write(*,*) "Invalid object passed to the append method. Source must be of class symba_pl or its descendents!"
          call util_exit(FAILURE)
       end select
 
@@ -131,7 +131,7 @@ module subroutine symba_util_append_tp(self, source, lsource_mask)
 
          call util_append_tp(self, source, lsource_mask) ! Note: helio_tp does not have its own append method, so we skip back to the base class
       class default
-         write(*,*) "Invalid object passed to the append method. Source must be of class symba_tp or its descendents"
+         write(*,*) "Invalid object passed to the append method. Source must be of class symba_tp or its descendents!"
          call util_exit(FAILURE)
       end select
 
@@ -254,7 +254,8 @@ module subroutine symba_util_fill_pl(self, inserts, lfill_list)
             
             call util_fill_pl(keeps, inserts, lfill_list)  ! Note: helio_pl does not have its own fill method, so we skip back to the base class
          class default
-            write(*,*) 'Error! fill method called for incompatible return type on symba_pl'
+            write(*,*) "Invalid object passed to the fill method. Source must be of class symba_pl or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate
 
@@ -283,7 +284,8 @@ module subroutine symba_util_fill_tp(self, inserts, lfill_list)
             
             call util_fill_tp(keeps, inserts, lfill_list) ! Note: helio_tp does not have its own fill method, so we skip back to the base class
          class default
-            write(*,*) 'Error! fill method called for incompatible return type on symba_tp'
+            write(*,*) "Invalid object passed to the fill method. Source must be of class symba_tp or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate
 
@@ -691,7 +693,8 @@ module subroutine symba_util_spill_pl(self, discards, lspill_list, ldestructive)
 
             call util_spill_pl(keeps, discards, lspill_list, ldestructive)
          class default
-            write(*,*) 'Error! spill method called for incompatible return type on symba_pl'
+            write(*,*) "Invalid object passed to the spill method. Source must be of class symba_pl or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate
      
@@ -724,7 +727,8 @@ module subroutine symba_util_spill_tp(self, discards, lspill_list, ldestructive)
 
             call util_spill_tp(keeps, discards, lspill_list, ldestructive)
          class default
-            write(*,*) 'Error! spill method called for incompatible return type on symba_pl'
+            write(*,*) "Invalid object passed to the spill method. Source must be of class symba_tp or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate
      
diff --git a/src/whm/whm_util.f90 b/src/whm/whm_util.f90
index 5a095192c..4dbc81fb7 100644
--- a/src/whm/whm_util.f90
+++ b/src/whm/whm_util.f90
@@ -56,7 +56,7 @@ module subroutine whm_util_fill_pl(self, inserts, lfill_list)
 
             call util_fill_pl(keeps, inserts, lfill_list)
          class default
-            write(*,*) "Invalid object passed to the fill method. Inserts must be of class whm_pl or its descendents"
+            write(*,*) "Invalid object passed to the fill method. Inserts must be of class whm_pl or its descendents!"
             call util_exit(FAILURE)
          end select
       end associate
@@ -209,7 +209,8 @@ module subroutine whm_util_spill_pl(self, discards, lspill_list, ldestructive)
 
             call util_spill_pl(keeps, discards, lspill_list, ldestructive)
          class default
-            write(*,*) 'Error! spill method called for incompatible return type on whm_pl'
+            write(*,*) "Invalid object passed to the spill method. Source must be of class whm_pl or its descendents!"
+            call util_exit(FAILURE)
          end select
       end associate