diff --git a/siteupdate/cplusplus/Makefile b/siteupdate/cplusplus/Makefile
index e123ac1..f93cf29 100644
--- a/siteupdate/cplusplus/Makefile
+++ b/siteupdate/cplusplus/Makefile
@@ -43,6 +43,7 @@ CommonObjects = \
   classes/Waypoint/Waypoint.o \
   classes/Waypoint/canonical_waypoint_name/canonical_waypoint_name.o \
   functions/crawl_rte_data.o \
+  functions/failure_cleanup.o \
   functions/rdstats.o \
   functions/route_and_label_logs.o \
   functions/tmstring.o
diff --git a/siteupdate/cplusplus/functions/failure_cleanup.cpp b/siteupdate/cplusplus/functions/failure_cleanup.cpp
new file mode 100644
index 0000000..afd9eea
--- /dev/null
+++ b/siteupdate/cplusplus/functions/failure_cleanup.cpp
@@ -0,0 +1,20 @@
+#include "../classes/Args/Args.h"
+#include "../classes/GraphGeneration/GraphListEntry.h"
+#include "../classes/GraphGeneration/PlaceRadius.h"
+#include "../classes/WaypointQuadtree/WaypointQuadtree.h"
+#include <vector>
+
+void failure_cleanup
+(	WaypointQuadtree& all_waypoints, std::vector<unsigned int>& colocate_counts,
+	std::list<std::string*>& updates, std::list<std::string*>& systemupdates
+)
+{	Args::colocationlimit = 0;			// silence colocation reports
+	all_waypoints.final_report(colocate_counts);	// destroy quadtree nodes & colocation lists
+	for (auto g = GraphListEntry::entries.begin(); g < GraphListEntry::entries.end(); g += 3)
+	{	delete g->regions;			// destroy
+		delete g->systems;			// GraphListEntry
+		delete g->placeradius;			// data
+	}
+	for (std::string* u : updates)		delete[] u; // destroy updates
+	for (std::string* u : systemupdates)	delete[] u; // & systemupdates
+}
diff --git a/siteupdate/cplusplus/siteupdate.cpp b/siteupdate/cplusplus/siteupdate.cpp
index 2ef83fe..10dbe45 100644
--- a/siteupdate/cplusplus/siteupdate.cpp
+++ b/siteupdate/cplusplus/siteupdate.cpp
@@ -1,12 +1,12 @@
 // Tab Width = 8
 
-// Travel Mapping Project, Jim Teresco and Eric Bryant, 2015-2024
+// Travel Mapping Project, Jim Teresco and Eric Bryant, 2015-2026
 /* Code to read .csv and .wpt files and prepare for
 adding to the Travel Mapping Project database.
 
-(c) 2015-2024, Jim Teresco and Eric Bryant
+(c) 2015-2026, Jim Teresco and Eric Bryant
 Original Python version by Jim Teresco, with contributions from Eric Bryant and the TravelMapping team
-C++ translation by Eric Bryant
+C++ version by Eric Bryant and Jim Teresco
 
 This module defines classes to represent the contents of a
 .csv file that lists the highways within a system, and a
@@ -39,9 +39,10 @@ This module defines classes to represent the contents of a
 #include <thread>
 #include "threads/threads.h"
 #endif
-void allbyregionactiveonly(std::mutex*, double);
-void allbyregionactivepreview(std::mutex*, double);
 using namespace std;
+void allbyregionactiveonly(mutex*, double);
+void allbyregionactivepreview(mutex*, double);
+void failure_cleanup(WaypointQuadtree&, vector<unsigned int>&, list<string*>&, list<string*>&);
 
 int main(int argc, char *argv[])
 {	ifstream file;
@@ -50,6 +51,7 @@ int main(int argc, char *argv[])
 	ErrorList el;
 	double active_only_miles = 0;
 	double active_preview_miles = 0;
+	vector<unsigned int> colocate_counts(2,0);
 
 	// argument parsing
 	if (Args::init(argc, argv)) return 1;
@@ -198,6 +200,7 @@ int main(int argc, char *argv[])
 	{	cout << et.et() << "ABORTING due to " << el.error_list.size() << " errors:" << endl;
 		for (unsigned int i = 0; i < el.error_list.size(); i++)
 			cout << i+1 << ": " << el.error_list[i] << endl;
+		failure_cleanup(all_waypoints, colocate_counts, updates, systemupdates);
 		return 1;
 	}
 
@@ -228,64 +231,7 @@ int main(int argc, char *argv[])
 	     }
 
 	// print some statistics
-	cout << et.et() << "Processed " << HighwaySystem::syslist.size << " highway systems." << endl;
-	unsigned int routes = 0;
-	unsigned int points = 0;
-	unsigned int segments = 0;
-	for (HighwaySystem& h : HighwaySystem::syslist)
-	{	routes += h.routes.size;
-		for (Route& r : h.routes)
-		{	points += r.points.size;
-			segments += r.segments.size;
-		}
-	}
-	cout << "Processed " << routes << " routes with a total of " << points << " points and " << segments << " segments." << endl;
-	if (points != all_waypoints.size())
-	  cout << "MISMATCH: all_waypoints contains " << all_waypoints.size() << " waypoints!" << endl;
-	cout << et.et() << "WaypointQuadtree contains " << all_waypoints.total_nodes() << " total nodes." << endl;
-
-	vector<unsigned int> colocate_counts(2,0);
-	if (!Args::errorcheck)
-	{	// compute colocation of waypoints stats
-	        cout << et.et() << "Computing waypoint colocation stats";
-	        if (Args::colocationlimit)
-		  {   cout << ", reporting all with " << Args::colocationlimit << " or more colocations:" << endl;
-		  }
-		else
-		  {   cout << "." << endl;
-		  }
-		all_waypoints.final_report(colocate_counts);
-		cout << "Waypoint colocation counts:" << endl;
-		unsigned int unique_locations = 0;
-		for (unsigned int c = 1; c < colocate_counts.size(); c++)
-		{	unique_locations += colocate_counts[c];
-			printf("%6i are each occupied by %2i waypoints.\n", colocate_counts[c], c);
-		}
-		cout << "Unique locations: " << unique_locations << endl;
-	} else	all_waypoints.final_report(colocate_counts);
-
-	/* EDB
-	cout << endl;
-	unsigned int a_count = 0;
-	unsigned int p_count = 0;
-	unsigned int d_count = 0;
-	unsigned other_count = 0;
-	unsigned int total_rtes = 0;
-	for (HighwaySystem& h : HighwaySystem::syslist)
-	  for (Route* r : h.route_list)
-	  {	total_rtes++;
-		if (h.devel()) d_count++;
-		else {	if (h.active()) a_count++;
-			else if (h.preview()) p_count++;
-			     else other_count++;
-		     }
-	  }
-	cout << a_count+p_count << " clinchable routes:" << endl;
-	cout << a_count << " in active systems, and" << endl;
-	cout << p_count << " in preview systems." << endl;
-	cout << d_count << " routes in devel systems." << endl;
-	if (other_count) cout << other_count << " routes not designated active/preview/devel!" << endl;
-	cout << total_rtes << " total routes." << endl;//*/
+	#include "tasks/final_stats.cpp"
 
 	if (Args::errorcheck)
 	    cout << "\n!!! DATA CHECK SUCCESSFUL !!!\n" << endl;
diff --git a/siteupdate/cplusplus/tasks/final_stats.cpp b/siteupdate/cplusplus/tasks/final_stats.cpp
new file mode 100644
index 0000000..1b1451c
--- /dev/null
+++ b/siteupdate/cplusplus/tasks/final_stats.cpp
@@ -0,0 +1,31 @@
+cout << et.et() << "Processed " << HighwaySystem::syslist.size << " highway systems." << endl;
+unsigned int routes = 0;
+unsigned int points = 0;
+unsigned int segments = 0;
+for (HighwaySystem& h : HighwaySystem::syslist)
+{	routes += h.routes.size;
+	for (Route& r : h.routes)
+	{	points += r.points.size;
+		segments += r.segments.size;
+	}
+}
+cout << "Processed " << routes << " routes with a total of " << points << " points and " << segments << " segments." << endl;
+if (points != all_waypoints.size())
+  cout << "MISMATCH: all_waypoints contains " << all_waypoints.size() << " waypoints!" << endl;
+cout << et.et() << "WaypointQuadtree contains " << all_waypoints.total_nodes() << " total nodes." << endl;
+
+if (!Args::errorcheck)
+{	// compute colocation of waypoints stats
+        cout << et.et() << "Computing waypoint colocation stats";
+        if (Args::colocationlimit)
+		cout << ", reporting all with " << Args::colocationlimit << " or more colocations:" << endl;
+	else	cout << "." << endl;
+	all_waypoints.final_report(colocate_counts);
+	cout << "Waypoint colocation counts:" << endl;
+	unsigned int unique_locations = 0;
+	for (unsigned int c = 1; c < colocate_counts.size(); c++)
+	{	unique_locations += colocate_counts[c];
+		printf("%6i are each occupied by %2i waypoints.\n", colocate_counts[c], c);
+	}
+	cout << "Unique locations: " << unique_locations << endl;
+} else	all_waypoints.final_report(colocate_counts);
diff --git a/siteupdate/cplusplus/tasks/read_updates.cpp b/siteupdate/cplusplus/tasks/read_updates.cpp
index afca081..d607cca 100644
--- a/siteupdate/cplusplus/tasks/read_updates.cpp
+++ b/siteupdate/cplusplus/tasks/read_updates.cpp
@@ -13,6 +13,7 @@ while (getline(file, line))
 	size_t NumFields = 5;
 	string* fields = new string[5];
 			 // deleted as DB table is written
+			 // or when aborting due to ErrorList errors
 	string* ptr_array[5] = {&fields[0], &fields[1], &fields[2], &fields[3], &fields[4]};
 	split(line, ptr_array, NumFields, ';');
 	if (NumFields != 5)
@@ -75,6 +76,7 @@ while (getline(file, line))
 	size_t NumFields = 5;
 	string* fields = new string[5];
 			 // deleted as DB table is written
+			 // or when aborting due to ErrorList errors
 	string* ptr_array[5] = {&fields[0], &fields[1], &fields[2], &fields[3], &fields[4]};
 	split(line, ptr_array, NumFields, ';');
 	if (NumFields != 5)
diff --git a/siteupdate/cplusplus/tasks/subgraphs/area.cpp b/siteupdate/cplusplus/tasks/subgraphs/area.cpp
index dee75c8..ebf6259 100644
--- a/siteupdate/cplusplus/tasks/subgraphs/area.cpp
+++ b/siteupdate/cplusplus/tasks/subgraphs/area.cpp
@@ -33,6 +33,7 @@ while (getline(file, line))
 	if (*endptr || r <= 0) {el.add_error("invalid radius in areagraphs.csv line: " + line); r=1;}
 	PlaceRadius *a = new PlaceRadius(fields[0], fields[1], lat, lng, r);
 			 // deleted @ end of HighwayGraph::write_subgraphs_tmg
+			 // or when aborting due to ErrorList errors
 	GraphListEntry::add_group(
 		string(fields[1]) + fields[4] + "-area",
 		string(fields[0]) + " (" + fields[4] + " mi radius)",
diff --git a/siteupdate/cplusplus/tasks/subgraphs/continent.cpp b/siteupdate/cplusplus/tasks/subgraphs/continent.cpp
index 1558f43..6e134fd 100644
--- a/siteupdate/cplusplus/tasks/subgraphs/continent.cpp
+++ b/siteupdate/cplusplus/tasks/subgraphs/continent.cpp
@@ -2,6 +2,7 @@
 for (auto c = Region::continents.data(), dummy = c+Region::continents.size()-1; c < dummy; c++)
 {	regions = new vector<Region*>;
 		  // deleted @ end of HighwayGraph::write_subgraphs_tmg
+		  // or when aborting due to ErrorList errors
 	for (Region& r : Region::allregions)
 	  // does it match this continent and have routes?
 	  if (c == r.continent && r.active_preview_mileage)
diff --git a/siteupdate/cplusplus/tasks/subgraphs/country.cpp b/siteupdate/cplusplus/tasks/subgraphs/country.cpp
index 4a628e5..2b0faaa 100644
--- a/siteupdate/cplusplus/tasks/subgraphs/country.cpp
+++ b/siteupdate/cplusplus/tasks/subgraphs/country.cpp
@@ -2,6 +2,7 @@
 for (auto c = Region::countries.data(), dummy = c+Region::countries.size()-1; c < dummy; c++)
 {	regions = new vector<Region*>;
 		  // deleted @ end of HighwayGraph::write_subgraphs_tmg
+		  // or when aborting due to ErrorList errors
 	for (Region& r : Region::allregions)
 	  // does it match this country and have routes?
 	  if (c == r.country && r.active_preview_mileage)
diff --git a/siteupdate/cplusplus/tasks/subgraphs/fullcustom.cpp b/siteupdate/cplusplus/tasks/subgraphs/fullcustom.cpp
index c0c2e61..a451280 100644
--- a/siteupdate/cplusplus/tasks/subgraphs/fullcustom.cpp
+++ b/siteupdate/cplusplus/tasks/subgraphs/fullcustom.cpp
@@ -35,7 +35,7 @@ if (file.is_open())
 			double r = strtod(radius.data(), &endptr);
 			if (*endptr || r <= 0)	{el.add_error("invalid radius in fullcustom.csv line: " + line); ok = 0;}
 			a = new PlaceRadius(descr.data(), root.data(), lat, lng, r);
-		}	    // deleted @ end of HighwayGraph::write_subgraphs_tmg
+		}	    // deleted @ end of HighwayGraph::write_subgraphs_tmg or when aborting due to ErrorList errors
 		else if (blanks != 3)
 		{	el.add_error("lat/lng/radius error in fullcustom.csv line: [" + line
 				   + "], either all or none must be populated");
@@ -51,6 +51,7 @@ if (file.is_open())
 		if (regionlist.empty()) regions = 0;
 		else {	regions = new vector<Region*>;
 				  // deleted @ end of HighwayGraph::write_subgraphs_tmg
+				  // or when aborting due to ErrorList errors
 			char* field = new char[regionlist.size()+1];
 				      // deleted once region tokens are processed
 			strcpy(field, regionlist.data());
@@ -68,6 +69,7 @@ if (file.is_open())
 		if (systemlist.empty()) systems = 0;
 		else {	systems = new vector<HighwaySystem*>;
 				  // deleted @ end of HighwayGraph::write_subgraphs_tmg
+				  // or when aborting due to ErrorList errors
 			char* field = new char[systemlist.size()+1];
 				      // deleted once system tokens are processed
 			strcpy(field, systemlist.data());
diff --git a/siteupdate/cplusplus/tasks/subgraphs/multiregion.cpp b/siteupdate/cplusplus/tasks/subgraphs/multiregion.cpp
index 4d879f3..7daef35 100644
--- a/siteupdate/cplusplus/tasks/subgraphs/multiregion.cpp
+++ b/siteupdate/cplusplus/tasks/subgraphs/multiregion.cpp
@@ -23,6 +23,7 @@ while (getline(file, line))
 		     + " bytes in multiregion.csv line: " + line);
 	regions = new vector<Region*>;
 		  // deleted @ end of HighwayGraph::write_subgraphs_tmg
+		  // or when aborting due to ErrorList errors
 	for(char* rg = strtok(fields[2], ","); rg; rg = strtok(0, ","))
 	  try {	regions->push_back(Region::code_hash.at(rg));
 	      }
diff --git a/siteupdate/cplusplus/tasks/subgraphs/multisystem.cpp b/siteupdate/cplusplus/tasks/subgraphs/multisystem.cpp
index 563547f..39be1a8 100644
--- a/siteupdate/cplusplus/tasks/subgraphs/multisystem.cpp
+++ b/siteupdate/cplusplus/tasks/subgraphs/multisystem.cpp
@@ -23,6 +23,7 @@ while (getline(file, line))
 		     + " bytes in multisystem.csv line: " + line);
 	systems = new vector<HighwaySystem*>;
 		  // deleted @ end of HighwayGraph::write_subgraphs_tmg
+		  // or when aborting due to ErrorList errors
 	for(char* s = strtok(fields[2], ","); s; s = strtok(0, ","))
 	  try {	HighwaySystem* const h = HighwaySystem::sysname_hash.at(s);
 		if (h->active_or_preview())
diff --git a/siteupdate/cplusplus/tasks/subgraphs/region.cpp b/siteupdate/cplusplus/tasks/subgraphs/region.cpp
index 4be8971..0e6367c 100644
--- a/siteupdate/cplusplus/tasks/subgraphs/region.cpp
+++ b/siteupdate/cplusplus/tasks/subgraphs/region.cpp
@@ -6,5 +6,5 @@ for (Region& region : Region::allregions)
 		region.name + " (" + region.type + ")", 'r',
 		new vector<Region*>(1, &region), nullptr, nullptr);
 		// deleted @ end of HighwayGraph::write_subgraphs_tmg
-}
+}		// or when aborting due to ErrorList errors
 graph_types.push_back({"region", "Routes Within a Single Region", "These graphs contain all routes currently plotted within the given region."});
diff --git a/siteupdate/cplusplus/tasks/subgraphs/system.cpp b/siteupdate/cplusplus/tasks/subgraphs/system.cpp
index 164f753..c6d29ce 100644
--- a/siteupdate/cplusplus/tasks/subgraphs/system.cpp
+++ b/siteupdate/cplusplus/tasks/subgraphs/system.cpp
@@ -10,6 +10,7 @@ while (getline(file, line))
 		h->systemname + " (" + h->fullname + ")",
 		's', nullptr, new vector<HighwaySystem*>(1, h), nullptr);
 			      // deleted @ end of HighwayGraph::write_subgraphs_tmg
+			      // or when aborting due to ErrorList errors
 	    h->is_subgraph_system = 1;
 	} else el.add_error("devel system "+h->systemname+" in systemgraphs.csv");
       }
diff --git a/siteupdate/cplusplus/tasks/threaded/ReadList.cpp b/siteupdate/cplusplus/tasks/threaded/ReadList.cpp
index 1eca76d..432624c 100644
--- a/siteupdate/cplusplus/tasks/threaded/ReadList.cpp
+++ b/siteupdate/cplusplus/tasks/threaded/ReadList.cpp
@@ -8,7 +8,8 @@
 		// placement new
       #endif
 	if (TravelerList::file_not_found)
-	  {	cout << "\nCheck for typos in your -U or --userlist arguments, and make sure " << Args::userlistext << " files for all specified users exist.\nAborting." << endl;
+	{	cout << "\nCheck for typos in your -U or --userlist arguments, and make sure " << Args::userlistext << " files for all specified users exist.\nAborting." << endl;
+		failure_cleanup(all_waypoints, colocate_counts, updates, systemupdates);
 		return 1;
 	}
 	TravelerList::ids.clear();