Cannot modify header information - headers already sent by

Cannot modify header information - headers already sent by..
system\application\libraries\Userauth.php:272
i hate this kind of error.. it is simple but not the solution of fixing them is not properly
what the hell... i must configure my xampp not to auto start the session..
which one is proper will be choosen..

lets check it out which area area effected or maybe we can just edit the php.ini not to auto start the session

but remember this line
//session_start(); // line 130 in session.php