Enabling searching in Drupal is easy enough, but a lot of people have trouble enabling the advanced searching capabilities in Drupal. Once an administrator enables a search box, he or she will be able to access the advanced search form on the search page. The problem, however, is that normal and unregistered visitors cannot see it.

To fix this problem you need to navigate to Administer -> User Management -> Permissions. Scroll all the way down to the 'search module' section and check the two checkboxes for advanced searching like so:



If you just want registered users to access advanced searching, just check the rightmost box. Well that's about it! Now even non-administrators can use the advanced search in Drupal: