diff --git a/src/mapbuffer.cpp b/src/mapbuffer.cpp
index cc40e39d9f27f..6c32db50189be 100644
--- a/src/mapbuffer.cpp
+++ b/src/mapbuffer.cpp
@@ -21,6 +21,18 @@
 
 #define dbg(x) DebugLog((x),D_MAP) << __FILE__ << ":" << __LINE__ << ": "
 
+static std::string find_quad_path( const std::string &dirname, const tripoint &om_addr )
+{
+    return string_format( "%s/%d.%d.%d.map", dirname, om_addr.x, om_addr.y, om_addr.z );
+}
+
+static std::string find_dirname( const tripoint &om_addr )
+{
+    const tripoint segment_addr = omt_to_seg_copy( om_addr );
+    return string_format( "%s/maps/%d.%d.%d", g->get_world_base_save_path(), segment_addr.x,
+                          segment_addr.y, segment_addr.z );
+}
+
 mapbuffer MAPBUFFER;
 
 mapbuffer::mapbuffer() = default;
@@ -103,8 +115,7 @@ submap *mapbuffer::lookup_submap( const tripoint &p )
 
 void mapbuffer::save( bool delete_after_save )
 {
-    const std::string map_directory = g->get_world_base_save_path() + "/maps";
-    assure_dir_exist( map_directory );
+    assure_dir_exist( g->get_world_base_save_path() + "/maps" );
 
     int num_saved_submaps = 0;
     int num_total_submaps = submaps.size();
@@ -137,11 +148,8 @@ void mapbuffer::save( bool delete_after_save )
         // A segment is a chunk of 32x32 submap quads.
         // We're breaking them into subdirectories so there aren't too many files per directory.
         // Might want to make a set for this one too so it's only checked once per save().
-        tripoint segment_addr = omt_to_seg_copy( om_addr );
-        const std::string dirname = string_format( "%s/%d.%d.%d", map_directory, segment_addr.x,
-                                    segment_addr.y, segment_addr.z );
-        const std::string quad_path = string_format( "%s/%d.%d.%d.map", dirname, om_addr.x, om_addr.y,
-                                      om_addr.z );
+        const std::string dirname = find_dirname( om_addr );
+        const std::string quad_path = find_quad_path( dirname, om_addr );
 
         // delete_on_save deletes everything, otherwise delete submaps
         // outside the current map.
@@ -240,11 +248,20 @@ submap *mapbuffer::unserialize_submaps( const tripoint &p )
 {
     // Map the tripoint to the submap quad that stores it.
     const tripoint om_addr = sm_to_omt_copy( p );
-    const tripoint segment_addr = omt_to_seg_copy( om_addr );
-    const std::string dirname = string_format( "%s/maps/%d.%d.%d", g->get_world_base_save_path(),
-                                segment_addr.x, segment_addr.y, segment_addr.z );
-    const std::string quad_path = string_format( "%s/%d.%d.%d.map", dirname, om_addr.x, om_addr.y,
-                                  om_addr.z );
+    const std::string dirname = find_dirname( om_addr );
+    std::string quad_path = find_quad_path( dirname, om_addr );
+
+    if( !file_exist( quad_path ) ) {
+        // Fix for old saves where the path was generated using std::stringstream, which
+        // did format the number using the current locale. That formatting may insert
+        // thousands separators, so the resulting path is "map/1,234.7.8.map" instead
+        // of "map/1234.7.8.map".
+        std::ostringstream buffer;
+        buffer << dirname << "/" << om_addr.x << "." << om_addr.y << "." << om_addr.z << ".map";
+        if( file_exist( buffer.str() ) ) {
+            quad_path = buffer.str();
+        }
+    }
 
     using namespace std::placeholders;
     if( !read_from_file_optional_json( quad_path, std::bind( &mapbuffer::deserialize, this, _1 ) ) ) {