On 404 Not Found error pages, Drupal will skip rendering of several pieces of your website for performance reasons. Some of these include:
- The "Left" and "Right" regions of your theme.
- The "Primary links" block and any other menu links block.*
- The Primary links and Secondary links of your theme.*
* Unless you have configured a "Default 404 (not found) page" on admin/settings/error-reporting.
But many websites find those items invaluable. Especially on 404 pages, when they want to show lost users how to get to real pages.
So this module simply revives those features on 404 pages. Simply install and enable the module. No configuration needed.
Development is sponsored by Palantir.net.
Drupal 7 version
An attempt was made to deprecate this module by including its functionality in Drupal 7 core; see #233807: No navigation links on 404 pages and #423992: Remove show_blocks page variable. Unfortunately, only one of those issues was committed to Drupal 7. Since blocks now appear on 404 pages, but navigational links are still missing, this project is being renamed…
For a Drupal 7 version, see the 404 Navigation project.