You want to disable PHPBB forum logs that are added into a database and are also visible inside AdminCP homepage for example?

On PHPBB 3.3.x

in file

Code:
/phpbb/log/log.php
change on line 312

Code:
if (!isset($sql_ary['log_type']))
with

Code:
$disableLog =  true;
if (!isset($sql_ary['log_type']) OR $disableLog)
should work but actually under test.

On old PHPBB 3.0.x


in older PHPBB, there was not a log.php, but in includes/functions.php i have turned

$db->sql_query('INSERT INTO ' . LOG_TABLE . ' ' . $db->sql_build_array('INSERT', $sql_ary));

return $db->sql_nextid();
into

// $db->sql_query('INSERT INTO ' . LOG_TABLE . ' ' . $db->sql_build_array('INSERT', $sql_ary));

// return $db->sql_nextid();
(deactivating the code to insert new log lines by prefixing by "//")
I know it is not ideal.
Also delete existing logs.