diff --git a/Common/Octree.cpp b/Common/Octree.cpp
index a880fd2da7755356fea590608ea2e3b13ea37476..055a8ccb346a2d54e618f005731809c7f7dd70fa 100644
--- a/Common/Octree.cpp
+++ b/Common/Octree.cpp
@@ -46,6 +46,7 @@ void free_buckets(octantBucket * bucket)
 
 void Octree_Delete(Octree *myOctree)
 {
+  if(!myOctree) return;
   delete myOctree->info;
   free_buckets(myOctree->root);
   delete myOctree->root;
@@ -54,6 +55,7 @@ void Octree_Delete(Octree *myOctree)
 
 void Octree_Insert(void * element, Octree *myOctree)
 {
+  if(!myOctree) return;
   double minBB[3], maxBB[3], centroid[3];
   octantBucket *bucket;
   (*(myOctree->function_BB))(element, minBB, maxBB);
@@ -64,7 +66,8 @@ void Octree_Insert(void * element, Octree *myOctree)
 }
 
 void Octree_Arrange(Octree *myOctree)
-{  
+{
+  if(!myOctree) return;
   std::list<void *>::iterator iter;
   double minPt[3], maxPt[3];
   for(iter = myOctree->info->listAllElements.begin(); iter!= 
@@ -75,14 +78,16 @@ void Octree_Arrange(Octree *myOctree)
   myOctree->info->listAllElements.clear();
 }   
 
-void * Octree_Search(double *pt, Octree *myOctree)
+void *Octree_Search(double *pt, Octree *myOctree)
 {
+  if(!myOctree) return 0;
   return searchElement(myOctree->root, pt, myOctree->info, 
                        myOctree->function_BB, myOctree->function_inElement);
 }
 
-void Octree_SearchAll(double * pt, Octree * myOctree, std::list<void *> * output)
+void Octree_SearchAll(double *pt, Octree *myOctree, std::list<void*> *output)
 {
+  if(!myOctree) return;
   searchAllElements(myOctree->root, pt, myOctree->info, myOctree->function_BB,
                     myOctree->function_inElement, output);      
 }
diff --git a/Geo/GModel.cpp b/Geo/GModel.cpp
index a0f00bb5d79467ebe2fd87d5409b4f01abd5614f..cdbd9c3750cf9facdc4be8a6b8fc8176652c6ec8 100644
--- a/Geo/GModel.cpp
+++ b/Geo/GModel.cpp
@@ -203,7 +203,7 @@ void GModel::destroyMeshCaches()
   _vertexMapCache.clear();
   _elementVectorCache.clear();
   _elementMapCache.clear();
-  if(_octree) Octree_Delete(_octree);
+  Octree_Delete(_octree);
   _octree = 0;
 }
 
diff --git a/Geo/MElementOctree.cpp b/Geo/MElementOctree.cpp
index fe6e1a01280fe32fac72893d53e1b325af1feb95..b16d8aebbd4579abc33f9fc05825a1db06a262e2 100644
--- a/Geo/MElementOctree.cpp
+++ b/Geo/MElementOctree.cpp
@@ -1,3 +1,8 @@
+// Gmsh - Copyright (C) 1997-2010 C. Geuzaine, J.-F. Remacle
+//
+// See the LICENSE.txt file for license information. Please report all
+// bugs and problems to <gmsh@geuz.org>.
+
 #include "MElement.h"
 #include "GModel.h"
 #include "Octree.h"
diff --git a/Post/OctreePost.cpp b/Post/OctreePost.cpp
index a70f21228d2a5f5c96bcfacc58bf208198a56608..8850cf778829e76bb79e95bb2f7f9e11cbc80940 100644
--- a/Post/OctreePost.cpp
+++ b/Post/OctreePost.cpp
@@ -201,17 +201,19 @@ static void addListOfStuff(Octree *o, std::vector<double> &l, int nbelm)
 
 OctreePost::~OctreePost() 
 {
-  if(_ST) Octree_Delete(_ST); if(_VT) Octree_Delete(_VT); if(_TT) Octree_Delete(_TT);
-  if(_SQ) Octree_Delete(_SQ); if(_VQ) Octree_Delete(_VQ); if(_TQ) Octree_Delete(_TQ);
-  if(_SS) Octree_Delete(_SS); if(_VS) Octree_Delete(_VS); if(_TS) Octree_Delete(_TS);
-  if(_SH) Octree_Delete(_SH); if(_VH) Octree_Delete(_VH); if(_TH) Octree_Delete(_TH);
-  if(_SI) Octree_Delete(_SI); if(_VI) Octree_Delete(_VI); if(_TI) Octree_Delete(_TI);
-  if(_SY) Octree_Delete(_SY); if(_VY) Octree_Delete(_VY); if(_TY) Octree_Delete(_TY);
+  Octree_Delete(_SL); Octree_Delete(_VL); Octree_Delete(_TL);
+  Octree_Delete(_ST); Octree_Delete(_VT); Octree_Delete(_TT);
+  Octree_Delete(_SQ); Octree_Delete(_VQ); Octree_Delete(_TQ);
+  Octree_Delete(_SS); Octree_Delete(_VS); Octree_Delete(_TS);
+  Octree_Delete(_SH); Octree_Delete(_VH); Octree_Delete(_TH);
+  Octree_Delete(_SI); Octree_Delete(_VI); Octree_Delete(_TI);
+  Octree_Delete(_SY); Octree_Delete(_VY); Octree_Delete(_TY);
 }
 
 OctreePost::OctreePost(PView *v) 
-  : _ST(0), _VT(0), _TT(0), _SQ(0), _VQ(0), _TQ(0), _SS(0), _VS(0), _TS(0),
-    _SH(0), _VH(0), _TH(0), _SI(0), _VI(0), _TI(0), _SY(0), _VY(0), _TY(0),
+  : _SL(0), _VL(0), _TL(0), _ST(0), _VT(0), _TT(0), _SQ(0), _VQ(0), _TQ(0), 
+    _SS(0), _VS(0), _TS(0), _SH(0), _VH(0), _TH(0), _SI(0), _VI(0), _TI(0),
+    _SY(0), _VY(0), _TY(0),
     _theView(v), _theViewDataList(0), _theViewDataGModel(0)
 {
   _theViewDataGModel = dynamic_cast<PViewDataGModel*>(_theView->getData());
@@ -222,14 +224,21 @@ OctreePost::OctreePost(PView *v)
   _theViewDataList = dynamic_cast<PViewDataList*>(_theView->getData(true));
 
   if(_theViewDataList){
-    SBoundingBox3d bb = _theViewDataList->getBoundingBox();
+    PViewDataList *l = _theViewDataList;
+
+    if(l->haveInterpolationMatrices() && !_theView->getData()->isAdaptive()){
+      Msg::Error("Cannot create octree for non-adapted high-order view: you need");
+      Msg::Error("to select 'Adapt visualization grid' first");
+      return;
+    }
+
+    SBoundingBox3d bb = l->getBoundingBox();
     double min[3] = {bb.min().x(), bb.min().y(), bb.min().z()};
     double size[3] = {bb.max().x() - bb.min().x(),
                       bb.max().y() - bb.min().y(),
                       bb.max().z() - bb.min().z()};                   
     const int maxElePerBucket = 100; // memory vs. speed trade-off
     
-    PViewDataList *l = _theViewDataList;
     _SL = Octree_Create(maxElePerBucket, min, size, linBB, linCentroid, linInEle);
     addListOfStuff(_SL, l->SL, 6 + 2 * l->getNumTimeSteps());
     Octree_Arrange(_SL);