Final answer:
An author causes a broken link by renaming an item without updating all references to its old name, leading to errors when accessing the item via its previous path.
Step-by-step explanation:
An author can cause a broken link when renaming an item if they do not update all references to that item's old name. This typically happens in websites or digital documents where a file or page is linked using a specific path. When the file or page is renamed, the path changes. If the author doesn't update the links in all locations that refer to the renamed file or page, users will encounter a 404 error or broken link message when they try to access the item through its old name.