diff --git a/Event/EventOverlay/EventOverlayJobTransforms/share/skeleton.combinedinput.py b/Event/EventOverlay/EventOverlayJobTransforms/share/skeleton.combinedinput.py
index 230785022c1b01ec210eac42de1ab5c6fe3a787d..fd4bca4e8261883342d9ba544270e3c1f56f85ef 100644
--- a/Event/EventOverlay/EventOverlayJobTransforms/share/skeleton.combinedinput.py
+++ b/Event/EventOverlay/EventOverlayJobTransforms/share/skeleton.combinedinput.py
@@ -152,10 +152,9 @@ if jobproperties.Beam.beamType.get_Value() != 'cosmics':
     else:
         simFlags.EventFilter.set_On()
 
-## Always enable the looper killer, unless it's been disabled
-if not hasattr(runArgs, "enableLooperKiller") or runArgs.enableLooperKiller:
-    simFlags.OptionalUserActionList.addAction('G4UA::LooperKillerTool')
-else:
+## The looper killer is on by default. Disable it if this is requested.
+if hasattr(runArgs, "enableLooperKiller") and not runArgs.enableLooperKiller:
+    simFlags.OptionalUserActionList.removeAction('G4UA::LooperKillerTool')
     atlasG4log.warning("The looper killer will NOT be run in this job.")
 
 include("G4AtlasApps/G4Atlas.flat.configuration.py")
diff --git a/Simulation/SimuJobTransforms/share/skeleton.EVGENtoHIT_ISF.py b/Simulation/SimuJobTransforms/share/skeleton.EVGENtoHIT_ISF.py
index 8f812a7425fb9898fc2c4f35a4da80213ee773bd..bb5445379fefa21a54638df304f71fba996d2465 100644
--- a/Simulation/SimuJobTransforms/share/skeleton.EVGENtoHIT_ISF.py
+++ b/Simulation/SimuJobTransforms/share/skeleton.EVGENtoHIT_ISF.py
@@ -246,10 +246,9 @@ try:
 except:
     atlasG4log.warning('Could not add TimingAlg, no timing info will be written out.')
 
-## Always enable the looper killer, unless it's been disabled
-if not hasattr(runArgs, "enableLooperKiller") or runArgs.enableLooperKiller:
-    simFlags.OptionalUserActionList.addAction('G4UA::LooperKillerTool')
-else:
+## The looper killer is on by default. Disable it if this is requested.
+if hasattr(runArgs, "enableLooperKiller") and not runArgs.enableLooperKiller:
+    simFlags.OptionalUserActionList.removeAction('G4UA::LooperKillerTool')
     atlasG4log.warning("The looper killer will NOT be run in this job.")
 
 #### *********** import ISF_Example code here **************** ####
diff --git a/Simulation/SimuJobTransforms/share/skeleton.EVGENtoHIT_MC12.py b/Simulation/SimuJobTransforms/share/skeleton.EVGENtoHIT_MC12.py
index cc3c0a672ad8f4b38d0735183c87dceee4862fa2..af14d358ac2e7c7e3c92f06730c6d257fd234519 100644
--- a/Simulation/SimuJobTransforms/share/skeleton.EVGENtoHIT_MC12.py
+++ b/Simulation/SimuJobTransforms/share/skeleton.EVGENtoHIT_MC12.py
@@ -222,10 +222,9 @@ if jobproperties.Beam.beamType.get_Value() != 'cosmics':
 
 include("G4AtlasApps/G4Atlas.flat.configuration.py")
 
-## Always enable the looper killer, unless it's been disabled
-if not hasattr(runArgs, "enableLooperKiller") or runArgs.enableLooperKiller:
-    simFlags.OptionalUserActionList.addAction('G4UA::LooperKillerTool')
-else:
+## The looper killer is on by default. Disable it if this is requested.
+if hasattr(runArgs, "enableLooperKiller") and not runArgs.enableLooperKiller:
+    simFlags.OptionalUserActionList.removeAction('G4UA::LooperKillerTool')
     atlasG4log.warning("The looper killer will NOT be run in this job.")
 
 try:
diff --git a/Simulation/SimuJobTransforms/share/skeleton.TestBeam.py b/Simulation/SimuJobTransforms/share/skeleton.TestBeam.py
index 2c88541b26e4c4ce5cc70e0ff3283d12422d96e1..b31eb4228c51ddfdd4397b95c3daaa5bd3f577ab 100644
--- a/Simulation/SimuJobTransforms/share/skeleton.TestBeam.py
+++ b/Simulation/SimuJobTransforms/share/skeleton.TestBeam.py
@@ -216,10 +216,9 @@ except:
 
 include('G4AtlasApps/Tile2000_2003.flat.configuration.py')#HACK - has to be here for TBDetDescrLoader
 
-## Always enable the looper killer, unless it's been disabled
-if not hasattr(runArgs, "enableLooperKiller") or runArgs.enableLooperKiller:
-    simFlags.OptionalUserActionList.addAction('G4UA::LooperKillerTool')
-else:
+## The looper killer is on by default. Disable it if this is requested.
+if hasattr(runArgs, "enableLooperKiller") and not runArgs.enableLooperKiller:
+    simFlags.OptionalUserActionList.removeAction('G4UA::LooperKillerTool')
     atlasG4log.warning("The looper killer will NOT be run in this job.")
 
 ## Add G4 alg to alg sequence
diff --git a/Tools/FullChainTransforms/share/FastChainSkeleton.EVGENtoRDO.py b/Tools/FullChainTransforms/share/FastChainSkeleton.EVGENtoRDO.py
index 2f9bd99f866a8397dda4a18f4b7c7f0feec488a7..fde12ad917fc9652f1a5bcb27957abf75fc7d78e 100644
--- a/Tools/FullChainTransforms/share/FastChainSkeleton.EVGENtoRDO.py
+++ b/Tools/FullChainTransforms/share/FastChainSkeleton.EVGENtoRDO.py
@@ -290,10 +290,9 @@ else:
 ## Don't use the SeedsG4 override
 simFlags.SeedsG4.set_Off()
 
-## Always enable the looper killer, unless it's been disabled
-if not hasattr(runArgs, "enableLooperKiller") or runArgs.enableLooperKiller:
-    simFlags.OptionalUserActionList.addAction('G4UA::LooperKillerTool', ['Step'])
-else:
+## The looper killer is on by default. Disable it if this is requested.
+if hasattr(runArgs, "enableLooperKiller") and not runArgs.enableLooperKiller:
+    simFlags.OptionalUserActionList.removeAction('G4UA::LooperKillerTool')
     fast_chain_log.warning("The looper killer will NOT be run in this job.")
 
 
diff --git a/Tools/FullChainTransforms/share/skeleton.EVGENtoRDO.py b/Tools/FullChainTransforms/share/skeleton.EVGENtoRDO.py
index 946160525a84c2901469f8ef6a5404ae6b203573..422b4986599d50f436e4e5c101c385071daaf692 100644
--- a/Tools/FullChainTransforms/share/skeleton.EVGENtoRDO.py
+++ b/Tools/FullChainTransforms/share/skeleton.EVGENtoRDO.py
@@ -172,10 +172,9 @@ else:
 ## Don't use the SeedsG4 override
 simFlags.SeedsG4.set_Off()
 
-## Always enable the looper killer, unless it's been disabled
-if not hasattr(runArgs, "enableLooperKiller") or runArgs.enableLooperKiller:
-    simFlags.OptionalUserActionList.addAction('G4UA::LooperKillerTool')
-else:
+## The looper killer is on by default. Disable it if this is requested.
+if hasattr(runArgs, "enableLooperKiller") and not runArgs.enableLooperKiller:
+    simFlags.OptionalUserActionList.removeAction('G4UA::LooperKillerTool')
     fast_chain_log.warning("The looper killer will NOT be run in this job.")