diff --git a/Trigger/TrigValidation/TriggerTest/share/testCommonSliceAthenaTrigRDOtoAOD.py b/Trigger/TrigValidation/TriggerTest/share/testCommonSliceAthenaTrigRDOtoAOD.py
index 37245eb29d762fa8f57605711601c804f763fce5..ee15054237ea320d5a6ab242a5ae19d438a21bed 100644
--- a/Trigger/TrigValidation/TriggerTest/share/testCommonSliceAthenaTrigRDOtoAOD.py
+++ b/Trigger/TrigValidation/TriggerTest/share/testCommonSliceAthenaTrigRDOtoAOD.py
@@ -200,6 +200,9 @@ if 'enableCostMonitoring' in dir() and bool(enableCostMonitoring) == True:
 #-----------------------------------------------------------
 include("RecExCommon/RecExCommon_topOptions.py")
 #-----------------------------------------------------------
+from LumiBlockComps.LumiBlockMuWriterDefault import LumiBlockMuWriterDefault
+LumiBlockMuWriterDefault()
+
 # post set up trigger monitoring
 if 'enableCostMonitoring' in dir() and bool(enableCostMonitoring) == True:
     import TriggerJobOpts.Modifiers