diff --git a/FullSimLight/src/MyDetectorConstruction.cc b/FullSimLight/src/MyDetectorConstruction.cc
index d02647c407af930f02d6df15db781536446952d1..c03c06f75b8be8858fb71dce73ae4a7c563ca85b 100644
--- a/FullSimLight/src/MyDetectorConstruction.cc
+++ b/FullSimLight/src/MyDetectorConstruction.cc
@@ -35,7 +35,7 @@
 #include "G4TsitourasRK45.hh"
 
 // Define G4ATLAS when linking with an atlas patch of G4
-#define G4ATLAS
+//#define G4ATLAS
 
 #ifdef G4ATLAS
 #include "G4AtlasRK4.hh"