Fixes / Word · Checked

Word "Error! Bookmark not defined.": what it means and how to fix it

Short answer

"Error! Bookmark not defined." means a field in your Word document, usually a table of contents page number or a cross-reference, points to a bookmark that no longer exists. If it just appeared, press Ctrl+Z to undo. Otherwise click in the table of contents, press F9 and choose "Update entire table" so Word rebuilds its links from your current headings.

What this message means

Word links tables of contents, cross-references and some page numbers to their targets with bookmarks. Many of these bookmarks are hidden (table of contents entries use ones named _Toc followed by a number). The text you see is produced by a field, and when that field updates and can't find its bookmark, Word puts "Error! Bookmark not defined." in its place. The bookmark usually goes missing because the heading, caption or text it was attached to was deleted, retyped or pasted over. Your content is still there. Only the link is broken, and updating the field again or pointing it at a new target fixes it.

Common causes

CauseHow to tell
A heading was deleted, retyped or pasted over, taking its hidden table of contents bookmark with it.The error appears in the page-number column of the table of contents, often on some lines but not all, and usually right after you edited headings or printed or saved as PDF.
A cross-reference points to a bookmark, heading, figure or endnote that was removed.The error is in body text (for example "see page Error! Bookmark not defined."). Right-click it and choose Toggle Field Codes. You will see something like { REF _Ref123456 \h } or { PAGEREF MyBookmark \h }.
Fields updated automatically when you printed or exported to PDF, which exposed links that were already broken.The document looks fine on screen, but the printout or PDF shows the error, or the error appears on screen right after printing or saving.
Track Changes was on when the table of contents was updated from its right-click menu.Track Changes is on (Review tab), and the whole table of contents fills with errors after you right-click it and choose Update Field > Update entire table.
The table of contents or cross-reference was copied from another document or built across several files (master document, subdocuments or RD fields).The bookmark name in the field code does not exist under Insert > Bookmark (tick "Hidden bookmarks" to see _Toc and _Ref names) in the current file.

How to fix it

1. Undo immediately

  1. If the error appeared just now and you have not closed the document, press Ctrl+Z (Cmd+Z on Mac).
  2. The previous page numbers or reference text come back.
  3. Before updating fields again, find and restore the heading or text you deleted, or use one of the fixes below.

2. Rebuild the table of contents

  1. Make sure every heading that should appear uses a built-in heading style (Heading 1, Heading 2 and so on) on the Home tab.
  2. Click anywhere inside the table of contents.
  3. Press F9 (on a Mac laptop you may need fn+F9), or go to References > Update Table.
  4. Choose "Update entire table" and click OK. Word creates new hidden bookmarks for the current headings.
  5. If errors remain, go to References > Table of Contents, pick the same style and accept replacing the existing table.

3. Turn off Track Changes before updating the table of contents

Word for Microsoft 365 and Word 2019/2021/2024 on Windows. On Mac, turn Track Changes off on the Review tab before updating.

  1. On the Review tab, turn off Track Changes.
  2. Update the table of contents with References > Update Table > Update entire table, not the right-click menu.
  3. If you have to keep Track Changes on, go to File > Options > Advanced and, under Print, change the "Allow fields containing tracked changes to update before printing" checkbox (tick it if it's cleared, clear it if it's ticked). Then test the update again.
  4. Turn Track Changes back on if you need it.

4. Repair or replace a broken cross-reference

  1. Right-click the error text and choose Toggle Field Codes to see the bookmark name the field is looking for.
  2. Go to Insert > Bookmark (Insert > Links > Bookmark in some layouts), tick "Hidden bookmarks", and check whether that name is in the list.
  3. If it's missing and you know where the target is, select the target text, type the exact bookmark name in Insert > Bookmark and click Add. Then right-click the field and choose Update Field.
  4. For headings, figures, tables or notes, it's often easier to delete the broken reference and insert a new one with References > Cross-reference (Insert > Cross-reference on Mac).
  5. Do not delete bookmarks you can't identify. Other cross-references may depend on them.

5. Show bookmarks so you don't delete them again

Menu paths differ between Word for Windows and Word for Mac, as shown in the steps.

  1. Windows: go to File > Options > Advanced and, under "Show document content", tick "Show bookmarks".
  2. Mac: go to Word > Preferences (Settings in newer versions) > View and tick Bookmarks.
  3. Bookmarked text now shows grey square brackets [like this], and a bookmark at a single point shows as an I-beam.
  4. When editing a heading or caption, change the text inside the brackets rather than deleting the whole thing.

6. Convert the fields to plain text (last resort)

  1. Select the table of contents or the paragraph containing the error.
  2. Press Ctrl+Shift+F9 on Windows (Cmd+Shift+F9 or Cmd+6 on Mac) to unlink the fields.
  3. The errors become ordinary text. Type the correct page numbers over them.
  4. The table of contents or reference will no longer update itself, so do this only on a final copy you are about to print or send as PDF.

Next time, skip the search

Crade is an AI assistant for Mac and Windows that sees your screen. When a message like this pops up, ask “what does this mean?” and it explains the exact error in front of you, step by step.

Download Crade

Still not fixed?

If the errors keep coming back after you rebuild the table of contents, save a copy of the file, turn off Track Changes, accept or reject all pending revisions (Review > Accept > Accept All Changes) and update the fields again, since deleted text still under revision is a common hidden cause. For long documents with many cross-references, press Alt+F9 (Option+F9 on Mac) to show all field codes and check each REF or PAGEREF name against the Insert > Bookmark list with hidden bookmarks shown. If the file came from a template, a document management system or a master document, ask whoever maintains that template. You can also report a suspected bug from Word with File > Feedback (Help > Feedback on Mac).

Questions people ask

Why does my table of contents say "Error! Bookmark not defined." only in the PDF?

Printing and Save as PDF update fields first, so any table of contents or cross-reference that lost its bookmark shows the error in the output. Update the table of contents on screen, fix any errors there, then export again.

Did I lose my content?

No. Only the link from the field to its target is broken. Your headings and text are unchanged, and the page numbers come back once the field can find its bookmark again.

I never created any bookmarks. Why is Word complaining about one?

Word creates hidden bookmarks automatically for tables of contents (_Toc names) and cross-references (_Ref names). To see them, tick "Hidden bookmarks" in Insert > Bookmark.

How do I get rid of the error without fixing every link?

Select the text and press Ctrl+Shift+F9 (Cmd+Shift+F9 on Mac) to convert the fields to plain text, then type the correct numbers. The table of contents will no longer update automatically.

Should I delete the bookmarks shown in brackets to stop the error?

No. Deleting bookmarks makes the error worse, because every field pointing to them breaks. Fix or re-insert the reference instead.

Sources

Related errors