diff --git a/PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/src/GenFilterTool.cxx b/PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/src/GenFilterTool.cxx
index 5c2b9c64d6b4f80bfb1fbfb91f5e3ab4bee1c007..8fca4f111bc93b5033a465603e8407eec9009b2d 100644
--- a/PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/src/GenFilterTool.cxx
+++ b/PhysicsAnalysis/DerivationFramework/DerivationFrameworkMCTruth/src/GenFilterTool.cxx
@@ -57,7 +57,7 @@ namespace DerivationFramework {
     ATH_MSG_VERBOSE("Particle has origin " << orig);
 
     switch(orig) {
-    case Unknown:
+    case NonDefined:
     case PhotonConv:
     case DalitzDec:
     case ElMagProc:
@@ -227,4 +227,4 @@ namespace DerivationFramework {
   }
 
 
-} /// namespace
\ No newline at end of file
+} /// namespace