Bookmarks in Microsoft Word are helpful features you can use to easily navigate large or complex documents or to create links and cross-references between different files. Unfortunately, they don’t always work as intended, and you may run into the “Bookmark not defined” error message or the “Reference source not found” error if your bookmarks haven’t been configured correctly.
This guide explains how to fix “bookmark not defined” in Word.
Before You Begin – Make Sure Bookmarks Are Visible
Before we look at any Microsoft Word “bookmark not defined” fix, it’s first important to make sure you’ve turned on visible bookmarks in your Word documents. Here’s how to do that:
Step 1. Open Word and click on “File,” followed by “Options.”
Step 2. Click on “Advanced” then scroll down to find the “Show bookmarks” option. Check the box beside it to enable visible bookmarks, then click on “OK” to confirm.
How to Fix “Bookmark Not Defined” in Word by Replacing the Missing or Broken Bookmark
One of the most common reasons you’ll see the “Bookmark not defined” or “Reference source not found” error is that a bookmark that previously existed has been broken or removed. You can therefore fix the issue by replacing the lost bookmark like so:
Step 1. Right-click on the error message and click on “Toggle field codes.”
Step 2. The error code should then transform to reveal more details about what is wrong. Usually, it will contain the exact name of the missing bookmark.
Step 3. Click on the “Insert” tab, then select “Bookmark.”
Step 4. In the pop-up box, type in the exact name of the bookmark you wish to recover and click the “Add” button.
Step 5. Right-click on the error again and select “Update Field.” The error message should then go away, and the bookmark will be restored.
Resolve the Bookmark Not Defined Error by Updating the Impacted Field
If you’re having “Bookmark not defined” errors in fields like tables of contents, you may be able to quickly resolve them by updating the affected field. This is very simple to do in just two clicks:
Step 1. Right-click on the affected field where the error message has appeared.
Step 2. Select “Update Field” to refresh the field and potentially resolve the issue.
How to Fix Bookmark Not Defined by Switching to Static Text
Converting fields from automated to static text may also help to resolve this error, especially if the error appears multiple times in a list of contents. Note, however, that once you switch to static text, the tables or fields will no longer update automatically. So this method only works on finished documents that don’t need any additional changes.
Step 1. Highlight the fields or tables with the error message(s).
Step 2. Press the “Ctrl,” “Shift,” and “F9” keys to switch to static text.
Fix Word Bookmark Not Defined With the Undo Command
If you notice the “Bookmark not defined” error message pop up suddenly while making a change to your document, another very easy fix is to simply undo whatever action caused the error to appear. You may have inadvertently changed a bookmark or reference, for example. Press “Ctrl” and “Z” together to undo your last action, and repeat the command multiple times, if needed, until the error goes away.
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Last updated on 04 September, 2025
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