<html> <head> <style> .hmmessage P { margin:0px; padding:0px } body.hmmessage { font-size: 10pt; font-family:Verdana } </style> </head> <body class='hmmessage'> Hi Anne<br><br>I think that you should hadd command to merge root file.<br>example hadd result.root file1.root file2.root file3.root ..... etc<br><br>Hope it work<br>BENZ<br><br /><hr />Get back to school stuff for them and cashback for you. <a href='http://www.bing.com/cashback?form=MSHYCB&publ=WLHMTAG&crea=TEXT_MSHYCB_BackToSchool_Cashback_BTSCashback_1x1' target='_new'>Try BingT now.</a></body> </html>