Index: branches/Corsika7500Compatibility/msim/MPhotonData.h
===================================================================
--- branches/Corsika7500Compatibility/msim/MPhotonData.h	(revision 18454)
+++ branches/Corsika7500Compatibility/msim/MPhotonData.h	(revision 18455)
@@ -16,7 +16,7 @@
 #ifndef ROOT_TQuaternion
 #include <math.h>
-#define sqrt ::sqrt
+//#define sqrt ::sqrt
 #include <TQuaternion.h>
-#undef sqrt
+//#undef sqrt
 #endif
 
Index: branches/Corsika7500Compatibility/msim/MPhotonEvent.cc
===================================================================
--- branches/Corsika7500Compatibility/msim/MPhotonEvent.cc	(revision 18454)
+++ branches/Corsika7500Compatibility/msim/MPhotonEvent.cc	(revision 18455)
@@ -559,4 +559,6 @@
    fInFormat->Read(bunchHeader, 3 * sizeof(Int_t));
 
+   this->resize( bunchHeader[2] );   
+
    Int_t n = 0;
 
@@ -583,4 +585,6 @@
 {
    Int_t n = 0;
+
+   this->resize(numEvents);
 
    for (Int_t event = 0; event < numEvents; event++)
@@ -644,2 +648,8 @@
     }
 }
+
+void MPhotonEvent::Reset()
+{
+	this->Clear();
+	this->Resize(0);
+}
Index: branches/Corsika7500Compatibility/msim/MPhotonEvent.h
===================================================================
--- branches/Corsika7500Compatibility/msim/MPhotonEvent.h	(revision 18454)
+++ branches/Corsika7500Compatibility/msim/MPhotonEvent.h	(revision 18455)
@@ -70,4 +70,6 @@
     //void Clear(Option_t * = NULL);
 
+    void Reset();
+
     ClassDef(MPhotonEvent, 1) //Container to store the raw Event Data
 };