Index: trunk/Mars/mmc/MMcEvt.cxx
===================================================================
--- trunk/Mars/mmc/MMcEvt.cxx	(revision 19953)
+++ trunk/Mars/mmc/MMcEvt.cxx	(revision 19954)
@@ -123,4 +123,6 @@
 void MMcEvt::Clear(Option_t *opt)
 {
+    fRunNumber = 0;
+
     fPartId = kUNDEFINED;
     fEnergy = -1;
@@ -272,5 +274,5 @@
 
     if (!fin.SetRefAddress("MMcEvt.fEvtNumber",         fEvtNumber        ))  return kFALSE;
-    if (!fin.SetRefAddress("MMcEvt.fRunNumber",         fRunNumber        ))  return kFALSE;
+    if (!fin.SetRefAddress("MMcEvt.fRunNumber",         fRunNumber        ))  { /* not in files < v7 */ }
     if (!fin.SetRefAddress("MMcEvt.fThick0",            fThick0           ))  return kFALSE;
     if (!fin.SetRefAddress("MMcEvt.fFirstTarget",       fFirstTarget      ))  return kFALSE;