diff --git a/PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/src/GenFilterTool.cxx b/PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/src/GenFilterTool.cxx
index 16d22fc47aa3aeca501d74599c5a291f2fe366ca..0e37ae5dcedf6d5098c0bdc40821e96aa4e87890 100644
--- a/PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/src/GenFilterTool.cxx
+++ b/PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/src/GenFilterTool.cxx
@@ -61,11 +61,11 @@ namespace DerivationFramework {
     ATH_MSG_VERBOSE("Particle has origin " << orig);
 
     switch(orig) {
+    case Unknown:
     case PhotonConv:
     case DalitzDec:
     case ElMagProc:
     case Mu:
-    case TauLep:
     case LightMeson:
     case StrangeMeson:
     case CharmedMeson: