Broken links happen when the page that a link points to is deleted, relocated, or has its slug changed.
When a page is deleted, pages linking to it have no way of “knowing” this, so the link remains but doesn’t go anywhere.
When a page is relocated to another place in the tree (i.e. it changes parents), pages linking to it do not have their links to it automatically updated.
When a page is renamed (i.e. its slug changes), the situation for pages linking to it is the same: their links remain, but they are no longer valid.
In all three scenarios, a visitor who clicks the link on Page A will not see Page B but rather a “File Not Found” page.
Avoiding Broken Links
To avoid this, links to pages that are deleted, relocated, or renamed must be manually updated. Page A in all three of these scenarios must have its link updated:
- If Page B is deleted, Page A must no longer link to it.
- If it is moved, Page A must link to the new location of Page B.
- If Page B is renamed to Page C, then Page A must now link to Page C.
It’s often necessary and appropriate to rename a page (change its slug). Just be aware that it has consequences for links on other pages. We in the marketing department get an email every time a visitor hits a broken link but receiving and correcting these is very time consuming, so make changes sensibly and try to clean up after yourself as much as you can.
Changing the location of a lower-level page likely has fewer implications than changing a higher-level page. Changing top-level pages’ slugs (e.g. alchemy-department to department-of-alchemy) should only be done in consultation with the marketing department.