diff --git a/src/DotRecast.Recast.Demo/Tools/TestNavmeshSampleTool.cs b/src/DotRecast.Recast.Demo/Tools/TestNavmeshSampleTool.cs
index a617d24..adde6e0 100644
--- a/src/DotRecast.Recast.Demo/Tools/TestNavmeshSampleTool.cs
+++ b/src/DotRecast.Recast.Demo/Tools/TestNavmeshSampleTool.cs
@@ -669,13 +669,9 @@ public class TestNavmeshSampleTool : ISampleTool
         }
         else if (_mode == RcTestNavmeshToolMode.PATHFIND_SLICED)
         {
-            m_polys = null;
-            m_straightPath = null;
-
-            if (m_sposSet && m_eposSet && m_startRef != 0 && m_endRef != 0)
-            {
-                m_pathFindStatus = _tool.InitSlicedFindPath(navQuery, m_startRef, m_endRef, m_spos, m_epos, m_filter, _enableRaycast);
-            }
+            m_polys?.Clear();
+            m_straightPath?.Clear();
+            m_pathFindStatus = _tool.InitSlicedFindPath(navQuery, m_startRef, m_endRef, m_spos, m_epos, m_filter, _enableRaycast);
         }
         else if (_mode == RcTestNavmeshToolMode.RAYCAST)
         {
@@ -708,7 +704,6 @@ public class TestNavmeshSampleTool : ISampleTool
 
     public void HandleUpdate(float dt)
     {
-        // TODO Auto-generated method stub
         if (_mode == RcTestNavmeshToolMode.PATHFIND_SLICED)
         {
             DtNavMeshQuery navQuery = _sample.GetNavMeshQuery();
diff --git a/src/DotRecast.Recast.Toolset/Tools/RcTestNavMeshTool.cs b/src/DotRecast.Recast.Toolset/Tools/RcTestNavMeshTool.cs
index 6bbb5bb..35bab9c 100644
--- a/src/DotRecast.Recast.Toolset/Tools/RcTestNavMeshTool.cs
+++ b/src/DotRecast.Recast.Toolset/Tools/RcTestNavMeshTool.cs
@@ -200,6 +200,11 @@ namespace DotRecast.Recast.Toolset.Tools
 
         public DtStatus InitSlicedFindPath(DtNavMeshQuery navQuery, long startRef, long endRef, RcVec3f startPos, RcVec3f endPos, IDtQueryFilter filter, bool enableRaycast)
         {
+            if (startRef == 0 || endRef == 0)
+            {
+                return DtStatus.DT_FAILURE;
+            }
+
             return navQuery.InitSlicedFindPath(startRef, endRef, startPos, endPos, filter,
                 enableRaycast ? DtNavMeshQuery.DT_FINDPATH_ANY_ANGLE : 0,
                 float.MaxValue