diff --git a/AtlasTest/DatabaseTest/AthenaPoolTest/share/AthenaPoolTestReadDoubleSelector.py b/AtlasTest/DatabaseTest/AthenaPoolTest/share/AthenaPoolTestReadDoubleSelector.py
index 620cb10f8c0179a34ca21c14896e0d73fa895308..30a5ee5da0f9fa3e26d56bdeb151fd8b8b55ec3d 100644
--- a/AtlasTest/DatabaseTest/AthenaPoolTest/share/AthenaPoolTestReadDoubleSelector.py
+++ b/AtlasTest/DatabaseTest/AthenaPoolTest/share/AthenaPoolTestReadDoubleSelector.py
@@ -23,6 +23,11 @@ from AthenaCommon.AppMgr import ServiceMgr as svcMgr
 ## get a handle to the ApplicationManager
 from AthenaCommon.AppMgr import theApp
 
+# Set that we are running MC+MC overlay in MT mode
+from OverlayCommonAlgs.OverlayFlags import overlayFlags
+overlayFlags.isDataOverlay.set_Value_and_Lock(False)
+overlayFlags.isOverlayMT.set_Value_and_Lock(True)
+
 #--------------------------------------------------------------
 # Load POOL support for DoubleEventSelector
 #--------------------------------------------------------------
diff --git a/AtlasTest/DatabaseTest/AthenaPoolTest/share/AthenaPoolTestStep2WriteDoubleSelector.py b/AtlasTest/DatabaseTest/AthenaPoolTest/share/AthenaPoolTestStep2WriteDoubleSelector.py
index 3e02a527833f7445986bb1b81e7151209557603d..705fac1159e50ab19a57d09e74ea4594459ebc06 100644
--- a/AtlasTest/DatabaseTest/AthenaPoolTest/share/AthenaPoolTestStep2WriteDoubleSelector.py
+++ b/AtlasTest/DatabaseTest/AthenaPoolTest/share/AthenaPoolTestStep2WriteDoubleSelector.py
@@ -24,6 +24,11 @@ from AthenaCommon.AppMgr import theApp
 ## get a handle to the ServiceManager
 from AthenaCommon.AppMgr import ServiceMgr as svcMgr
 
+# Set that we are running MC+MC overlay in MT mode
+from OverlayCommonAlgs.OverlayFlags import overlayFlags
+overlayFlags.isDataOverlay.set_Value_and_Lock(False)
+overlayFlags.isOverlayMT.set_Value_and_Lock(True)
+
 #--------------------------------------------------------------
 # Load POOL support for DoubleEventSelector
 #--------------------------------------------------------------
diff --git a/AtlasTest/DatabaseTest/AthenaPoolTest/share/DoubleEventSelectorOverlayTest.py b/AtlasTest/DatabaseTest/AthenaPoolTest/share/DoubleEventSelectorOverlayTest.py
index 1d4973c2165c302ffdf6d93b73a5884e6d5e22f3..244b2c99d0dd56bd1301b87bc69d4edb4d913d82 100644
--- a/AtlasTest/DatabaseTest/AthenaPoolTest/share/DoubleEventSelectorOverlayTest.py
+++ b/AtlasTest/DatabaseTest/AthenaPoolTest/share/DoubleEventSelectorOverlayTest.py
@@ -23,6 +23,11 @@ from AthenaCommon.AppMgr import ServiceMgr as svcMgr
 # get a handle to the ApplicationManager
 from AthenaCommon.AppMgr import theApp
 
+# Set that we are running MC+MC overlay in MT mode
+from OverlayCommonAlgs.OverlayFlags import overlayFlags
+overlayFlags.isDataOverlay.set_Value_and_Lock(False)
+overlayFlags.isOverlayMT.set_Value_and_Lock(True)
+
 #--------------------------------------------------------------
 # Load POOL support for DoubleEventSelector
 #--------------------------------------------------------------
diff --git a/AtlasTest/DatabaseTest/AthenaPoolTest/share/ReadRDODoubleSelector.py b/AtlasTest/DatabaseTest/AthenaPoolTest/share/ReadRDODoubleSelector.py
index 50f812c8b82b374cd8ea6fcb1a72732f8d5cb1df..1cfb91e267f8aff94b5d5bb73f208aa2be72029e 100644
--- a/AtlasTest/DatabaseTest/AthenaPoolTest/share/ReadRDODoubleSelector.py
+++ b/AtlasTest/DatabaseTest/AthenaPoolTest/share/ReadRDODoubleSelector.py
@@ -23,6 +23,11 @@ from AthenaCommon.AppMgr import ServiceMgr as svcMgr
 ## get a handle to the ApplicationManager
 from AthenaCommon.AppMgr import theApp
 
+# Set that we are running MC+MC overlay in MT mode
+from OverlayCommonAlgs.OverlayFlags import overlayFlags
+overlayFlags.isDataOverlay.set_Value_and_Lock(False)
+overlayFlags.isOverlayMT.set_Value_and_Lock(True)
+
 #--------------------------------------------------------------
 # Load POOL support for DoubleEventSelector
 #--------------------------------------------------------------