diff --git a/src/Mod/Mesh/App/Core/Visitor.cpp b/src/Mod/Mesh/App/Core/Visitor.cpp
index 2c9992d3d1..0400224308 100644
--- a/src/Mod/Mesh/App/Core/Visitor.cpp
+++ b/src/Mod/Mesh/App/Core/Visitor.cpp
@@ -40,6 +40,10 @@ unsigned long MeshKernel::VisitNeighbourFacets(MeshFacetVisitor& rclFVisitor,
     std::vector<FacetIndex>::iterator clCurrIter;
     MeshFacetArray::_TConstIterator clCurrFacet, clNBFacet;
 
+    if (ulStartFacet >= _aclFacetArray.size()) {
+        return 0;
+    }
+
     // pick up start point
     clCurrentLevel.push_back(ulStartFacet);
     _aclFacetArray[ulStartFacet].SetFlag(MeshFacet::VISIT);
@@ -98,6 +102,10 @@ unsigned long MeshKernel::VisitNeighbourFacetsOverCorners(MeshFacetVisitor& rclF
     MeshFacetArray::_TConstIterator pFBegin = raclFAry.begin();
     std::vector<FacetIndex> aclCurrentLevel, aclNextLevel;
 
+    if (ulStartFacet >= _aclFacetArray.size()) {
+        return 0;
+    }
+
     aclCurrentLevel.push_back(ulStartFacet);
     raclFAry[ulStartFacet].SetFlag(MeshFacet::VISIT);