Index: trunk/MagicSoft/Mars/mfileio/MReadTree.cc
===================================================================
--- trunk/MagicSoft/Mars/mfileio/MReadTree.cc	(revision 2984)
+++ trunk/MagicSoft/Mars/mfileio/MReadTree.cc	(revision 3009)
@@ -308,5 +308,5 @@
     // FIXME! A check is missing whether the file already exists or not.
     //
-    const Int_t numfiles = fChain->Add(fname, entries);
+    const Int_t numfiles = fChain->Add(fname, entries<0?TChain::kBigNumber:entries);
 
     if (numfiles>0)