diff --git a/grid/albertagrid/albertaextra.hh b/grid/albertagrid/albertaextra.hh
index b684659bc104b0c3363dc06c49fb43e595a0f4eb..16bd814d97d7f4c0a49121e14ebffacdd4ff489d 100644
--- a/grid/albertagrid/albertaextra.hh
+++ b/grid/albertagrid/albertaextra.hh
@@ -138,7 +138,7 @@ public:
     // if this assertion is thrown then either the stack = 0
     // or we want to uese the pointer but are not the owner
     assert( stack_ );
-    assert( owner_ );
+    assert( (!owner_) ? (std::cerr << "\nERROR:The feature of copying iterators is not supported by AlbertaGrid at the moment! \n\n", 0) : 1);
     return stack_;
   }
 private: