How to remove the unwanted tabs in drupal

The simple way to do this is need to customize the tabs in template.php file of the respective theme for ex>garland.

<?php
function yourthemename_preprocess_page(&$vars) {
  // Remove undesired local task tabs.
  // This first example removes the Users tab from the Search page.
  yourthemename_removetab('Users', $vars);
 yourthemename_removetab('By task', $vars);
}
?>

First to write above code for calling the removetab function.

<?php
// Remove undesired local task tabs.
// Related to yourthemename_removetab() in yourthemename_preprocess_page().
function yourthemename_removetab($label, &$vars) {
  $tabs = explode("\n", $vars['tabs']);
  $vars['tabs'] = '';

  foreach ($tabs as $tab) {
    if (strpos($tab, '>' . $label . '<') === FALSE) {
      $vars['tabs'] .= $tab . "\n";
    }
  }
}
?>

In this function you can remove the mentioned tab.

This code works for me.Hope this may little bit helps to you.