tip

Need to disable a Drupal module but can't do so from within the site? (This could happen if the wayward module is preventing you from reaching the Modules form!) Look for the module's entry within the "system" table of the site's database, and set the module's status to "0". 

(From within phpMyAdmin: Select the "system" table from the column of tables at left. Click the "Browse" tab. Find the row for the module you wish to disable, and click the "pencil" icon in that row. In the resulting form, input "0" for the Value of "status", and click the "Go" button. Done!) 

Within a Drupal site's database, it's safe to empty (that's empty, not drop) any table whose name begins with "cache". Emptying cache tables can sometimes fix persistent odd site behavior. (Safe or not, though, it's always a good idea to back up a database before performing any operations on it.)

As noted in Forum Finds: Node deletion is forever, when you tell Drupal to delete a node it gives you one "Are you sure...?" chance to recapitulate, but that's it. Confirm the deletion, and that node is gone; there's no Trash Can or Undo to get it back.

To prevent mishaps, be careful in giving users permission to delete nodes. Also, make it a rule to unpublish, not delete, nodes when you want to take them off the site. The node will disappear from view just as if it had been deleted, but will remain in the database should you ever want to republish, reedit, or otherwise revisit it.

Site visitors seeing your ugly error messages on the screen (along with details of your Drupal installation path)? Once your site goes from dev to launch, you probably want to have errors recorded in the log but not splashed across the screen. Head to the handy Error Reporting settings found at admin/settings/error-reporting. 

Tired of logging in again and again to a Drupal site that keeps kicking you out? You can modify session length, i.e. the length of time that a logged-in session stays logged in, via the ini_set('session.cookie_lifetime'... line in the site's settings.php file. See details in Forum Finds: Modify length of user login sessions.