diff --git a/Server/Map.cs b/Server/Map.cs
index b8837713e..fdf376278 100644
--- a/Server/Map.cs
+++ b/Server/Map.cs
@@ -939,9 +939,10 @@ namespace Server
 		{
 			get
 			{
-				lock (tileLock)
-					if ( m_Tiles == null )
-						m_Tiles = new TileMatrix( this, m_FileIndex, m_MapID, m_Width, m_Height );
+				if (m_Tiles == null)
+					lock (tileLock)
+						if (m_Tiles == null)
+							m_Tiles = new TileMatrix(this, m_FileIndex, m_MapID, m_Width, m_Height);
 
 				return m_Tiles;
 			}