Index: /trunk/Mars/mfileio/MReadMarsFile.cc
===================================================================
--- /trunk/Mars/mfileio/MReadMarsFile.cc	(revision 11455)
+++ /trunk/Mars/mfileio/MReadMarsFile.cc	(revision 11456)
@@ -272,13 +272,13 @@
     }
 
-    /*
-    const Int_t idx = GetFileIndex();
-    fRun->SetEventNum(idx<0?0:idx); // Assumption: One Entry per File!
-    if (!fRun->Process())
-    {
-        *fLog << err << "Error - Processing MReadMarsFile::fRun... aborting." << endl;
-        return kFALSE;
-    }
-    */
+    fRun->SetEventNum(0); 
+    const Int_t rc = fRun->Process();
+    if (rc!=kTRUE)
+    {
+        *fLog << err << "ERROR - Cannot read runheaders of first file.";
+        *fLog << " (MReadTree::Process() returned rc=" << rc << ")" << endl;
+        return kFALSE;
+    }
+
     return MReadTree::PreProcess(pList);
 }