diff --git a/Simulation/Tests/OverlayTestsMT/test/test_DataOverlay_MT_Zmumu_8threads_NewConfig.sh b/Simulation/Tests/OverlayTestsMT/test/test_DataOverlay_MT_Zmumu_8threads_NewConfig.sh
index 59e0a87d7c0dffdadcba260cd8a163544b19d30a..ba376114e655cbfe2958746dee95a45d62263707 100755
--- a/Simulation/Tests/OverlayTestsMT/test/test_DataOverlay_MT_Zmumu_8threads_NewConfig.sh
+++ b/Simulation/Tests/OverlayTestsMT/test/test_DataOverlay_MT_Zmumu_8threads_NewConfig.sh
@@ -26,7 +26,7 @@ echo "art-result: $rc overlay"
 # then
 #     ArtPackage=$1
 #     ArtJobName=$2
-#     art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --error-mode resilient --mode=semi-detailed --order-trees
+#     art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --error-mode resilient --mode=semi-detailed --order-trees --diff-root
 #     rc2=$?
 # fi
 # echo  "art-result: $rc2 regression"
diff --git a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MP_ttbar.sh b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MP_ttbar.sh
index cb7a9eea14999e624e94e4bafa533bdf5a9663a6..dce85040d9607def0d147eac7bae0d8bc7489dd1 100755
--- a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MP_ttbar.sh
+++ b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MP_ttbar.sh
@@ -31,7 +31,7 @@ if [ $rc -eq 0 ]
 then
     ArtPackage=$1
     ArtJobName=$2
-    art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --mode=semi-detailed --order-trees
+    art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --mode=semi-detailed --order-trees --diff-root
     rc2=$?
 fi
 echo  "art-result: $rc2 regression"
diff --git a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_1thread.sh b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_1thread.sh
index 92adcc7016258a8f2175620042fac7f13ab53516..108b20b6dc4ca032cfd04987e84d102866b2f990 100755
--- a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_1thread.sh
+++ b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_1thread.sh
@@ -32,7 +32,7 @@ if [ $rc -eq 0 ]
 then
     ArtPackage=$1
     ArtJobName=$2
-    art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --mode=semi-detailed
+    art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --mode=semi-detailed --diff-root
     rc2=$?
 fi
 echo "art-result: $rc2 regression"
diff --git a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_4threads.sh b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_4threads.sh
index 8b1ab81e23b535b869ca7463e74f335ca53fc395..f2950caed71c519e2d6ee5a9f61896465df68a7d 100755
--- a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_4threads.sh
+++ b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_4threads.sh
@@ -31,7 +31,7 @@ if [ $rc -eq 0 ]
 then
     ArtPackage=$1
     ArtJobName=$2
-    art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --mode=semi-detailed --order-trees
+    art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --mode=semi-detailed --order-trees --diff-root
     rc2=$?
 fi
 echo  "art-result: $rc2 regression"
diff --git a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_8threads_NewConfig.sh b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_8threads_NewConfig.sh
index c624ff1ad0e7fe77a86227ce1f1ee45b2be99e9b..b0a87f908bfe22653a6b1cb9e8e94d3eab29e9fb 100755
--- a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_8threads_NewConfig.sh
+++ b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_MT_ttbar_8threads_NewConfig.sh
@@ -26,7 +26,7 @@ echo "art-result: $rc overlay"
 # then
 #     ArtPackage=$1
 #     ArtJobName=$2
-#     art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --error-mode resilient --mode=semi-detailed --order-trees
+#     art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --error-mode resilient --mode=semi-detailed --order-trees --diff-root
 #     rc2=$?
 # fi
 # echo  "art-result: $rc2 regression"
diff --git a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_ttbar_ST_vs_MT.sh b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_ttbar_ST_vs_MT.sh
index c565afc3cb82a0cac3cd2d5c47ce378608a9d4d3..b351c7de68b072df6aebb30db21c7f1864f82ad4 100755
--- a/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_ttbar_ST_vs_MT.sh
+++ b/Simulation/Tests/OverlayTestsMT/test/test_MCOverlay_ttbar_ST_vs_MT.sh
@@ -58,7 +58,7 @@ if [ $rc2 -eq 0 ]
 then
     ArtPackage=$1
     ArtJobName=$2
-    art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --mode=semi-detailed --order-trees
+    art.py compare grid --entries 10 ${ArtPackage} ${ArtJobName} --mode=semi-detailed --order-trees --diff-root
     rc4=$?
 fi
 echo  "art-result: $rc4 regression"