Please modify the following lines in checkout_process.php
// do not decrement quantities if products_attributes_filename exists
if ((DOWNLOAD_ENABLED != 'true') || (!$stock_values['products_attributes_filename'])) {
$stock_left = $stock_values['products_quantity'] - $order->products[$i]['qty'];
} else {
$stock_left = $stock_values['products_quantity'];
}
tep_db_query("update " . TABLE_PRODUCTS . " set products_quantity = '" . $stock_left . "' where products_id = '" . tep_get_prid($order->products[$i]['id']) . "'");
if ($stock_left < 1) {
tep_db_query("update " . TABLE_PRODUCTS . " set products_status = '0' where products_id = '" . tep_get_prid($order->products[$i]['id']) . "'");
}
Mark the line as follows:
if ($stock_left < 1) {
# tep_db_query("update " . TABLE_PRODUCTS . " set products_status = '0' where products_id = '" . tep_get_prid($order->products[$i]['id']) . "'");
}
I hope it is helpful! :)