diff --git a/src/tools/mmaps_generator/MapBuilder.cpp b/src/tools/mmaps_generator/MapBuilder.cpp
index 3d912e5151..34a691c288 100644
--- a/src/tools/mmaps_generator/MapBuilder.cpp
+++ b/src/tools/mmaps_generator/MapBuilder.cpp
@@ -64,6 +64,8 @@ namespace MMAP
         m_skipBattlegrounds  (skipBattlegrounds),
         m_maxWalkableAngle   (maxWalkableAngle),
         m_bigBaseUnit        (bigBaseUnit),
+        m_totalTiles         (0u),
+        m_totalTilesProcessed(0u),
         m_rcContext          (NULL),
         _cancelationToken    (false)
     {
@@ -71,10 +73,6 @@ namespace MMAP
 
         m_rcContext = new rcContext(false);
 
-        // percentageDone - Initializing
-        m_totalTiles = 0;
-        m_totalTilesBuilt = 0;
-
         discoverTiles();
     }
 
@@ -155,8 +153,7 @@ namespace MMAP
         }
         printf("found %u.\n\n", count);
 
-        // percentageDone - total tiles to process
-        m_totalTiles = count;
+        m_totalTiles.store(count, std::memory_order_relaxed);
     }
 
     /**************************************************************************/
@@ -391,7 +388,8 @@ namespace MMAP
             // add all tiles within bounds to tile list.
             for (uint32 i = minX; i <= maxX; ++i)
                 for (uint32 j = minY; j <= maxY; ++j)
-                    tiles->insert(StaticMapTree::packTileID(i, j));
+                    if (tiles->insert(StaticMapTree::packTileID(i, j)).second)
+                        ++m_totalTiles;
         }
 
         if (!tiles->empty())
@@ -402,6 +400,7 @@ namespace MMAP
             if (!navMesh)
             {
                 printf("[Map %03i] Failed creating navmesh!\n", mapID);
+                m_totalTilesProcessed += tiles->size();
                 return;
             }
 
@@ -414,6 +413,7 @@ namespace MMAP
                 // unpack tile coords
                 StaticMapTree::unpackTileID((*it), tileX, tileY);
 
+                ++m_totalTilesProcessed;
                 if (shouldSkipTile(mapID, tileX, tileY))
                     continue;
 
@@ -429,8 +429,7 @@ namespace MMAP
     /**************************************************************************/
     void MapBuilder::buildTile(uint32 mapID, uint32 tileX, uint32 tileY, dtNavMesh* navMesh)
     {
-        // percentageDone - added, now it will show addional reference percentage done of the overall process
-        printf("%u%% [Map %03i] Building tile [%02u,%02u]\n", percentageDone(m_totalTiles, m_totalTilesBuilt), mapID, tileX, tileY);
+        printf("%u%% [Map %03i] Building tile [%02u,%02u]\n", percentageDone(m_totalTiles, m_totalTilesProcessed), mapID, tileX, tileY);
 
         MeshData meshData;
 
@@ -464,9 +463,6 @@ namespace MMAP
 
         // build navmesh tile
         buildMoveMapTile(mapID, tileX, tileY, meshData, bmin, bmax, navMesh);
-
-        // percentageDone - increment tiles built
-        m_totalTilesBuilt++;
     }
 
     /**************************************************************************/
diff --git a/src/tools/mmaps_generator/MapBuilder.h b/src/tools/mmaps_generator/MapBuilder.h
index 1bd2cbbbfd..2f47fdd0ff 100644
--- a/src/tools/mmaps_generator/MapBuilder.h
+++ b/src/tools/mmaps_generator/MapBuilder.h
@@ -123,7 +123,7 @@ namespace MMAP
             bool shouldSkipMap(uint32 mapID);
             bool isTransportMap(uint32 mapID);
             bool shouldSkipTile(uint32 mapID, uint32 tileX, uint32 tileY);
-            // percentageDone - method to calculate percentage
+
             uint32 percentageDone(uint32 totalTiles, uint32 totalTilesDone);
 
             TerrainBuilder* m_terrainBuilder;
@@ -138,9 +138,9 @@ namespace MMAP
 
             float m_maxWalkableAngle;
             bool m_bigBaseUnit;
-            // percentageDone - variables to calculate percentage
-            uint32 m_totalTiles;
-            std::atomic<uint32> m_totalTilesBuilt;
+
+            std::atomic<uint32> m_totalTiles;
+            std::atomic<uint32> m_totalTilesProcessed;
 
             // build performance - not really used for now
             rcContext* m_rcContext;