Microsoft 365 Copilot Cannot Summarize Document With Track Changes: Fix

You ask Copilot in Word to summarize a document that contains tracked changes. Instead of a summary, Copilot returns an error message or produces incomplete output. This problem occurs because Copilot reads the document’s current content plus the revision markup simultaneously, which creates conflicting data streams. This article explains the technical reason for the failure and provides a reliable fix so you can use Copilot to summarize documents that contain tracked changes.

Why Copilot Fails to Summarize Documents With Track Changes

Copilot in Word uses the Microsoft Graph and the document’s underlying text stream to generate summaries. When Track Changes is active, the document contains two overlapping text layers: the original text (shown with strikethrough or underlines) and the proposed revisions. Copilot’s summarization engine expects a single, unambiguous text stream. The presence of revision markup introduces conflicting data points that confuse the model. The model cannot determine which version of a sentence or paragraph to include in the summary. As a result, Copilot either refuses to generate a summary, produces a blank output, or returns an error message such as “Copilot cannot summarize this document.”

The same limitation applies to Copilot’s other content-generation features in Word, such as drafting or rewriting. The summarization feature is particularly sensitive because it requires a coherent, linear text flow. The revision markup breaks that flow.

Steps to Fix Copilot Summarization for Track-Changed Documents

The only reliable fix is to remove the revision markup from the document before you ask Copilot to summarize. This does not mean you lose the revision history. Use the following method to keep a separate copy of the track-changed version while giving Copilot a clean document to summarize.

1. Save a copy of the original document
   Press F12 to open the Save As dialog. Save a copy with a name like “Original_with_Track_Changes.docx.” This preserves the full revision history for reference.
2. Open the copy you will edit
   Close the original document. Open the copy you just saved. You will remove track changes from this copy.
3. Accept or reject all tracked changes
   Go to the Review tab. In the Changes group, click the Accept drop-down arrow. Select Accept All Changes. If you want to reject all changes instead, click the Reject drop-down arrow and select Reject All Changes. Either action clears the revision markup.
4. Turn off Track Changes
   Still on the Review tab, click Track Changes to turn it off. The button should no longer be highlighted. This prevents new edits from adding markup.
5. Save the clean document
   Press Ctrl+S to save the copy with all changes accepted and Track Changes disabled.
6. Ask Copilot to summarize
   Open the Copilot pane in Word by clicking the Copilot icon on the Home tab. Type a command such as “Summarize this document.” Copilot should now generate a summary based on the final, clean text.

Alternative Method: Use the Compare Tool to Preserve History

If you need to keep the track-changed document intact for legal or compliance reasons, use the Compare tool to create a clean version.

1. Open the original track-changed document
   Open the document that contains the tracked changes.
2. Accept all changes
   Go to Review > Accept > Accept All Changes.
3. Save the clean version
   Press F12 and save the document with a new name, such as “Clean_for_Copilot.docx.”
4. Reopen the original track-changed document
   Close the clean version and reopen the original track-changed document. Use the Compare tool to compare the two versions: Review > Compare > Compare. Select the original as the original document and the clean version as the revised document. Word creates a new document with revision marks showing the differences. This gives you a separate comparison document while keeping the original unchanged.
5. Use Copilot in the clean document
   Open the clean version you saved earlier. Ask Copilot to summarize. The original track-changed document remains untouched.

If Copilot Still Has Issues After the Main Fix

Copilot Returns an Error After All Changes Are Accepted

If you accepted all changes but Copilot still fails, the document may contain hidden revision markup from comments or ink annotations. Go to Review > Show Markup and uncheck Comments and Ink. Then try the summary command again. If the problem persists, save the document as a plain .docx file by using File > Save As > Word Document. Do not use the .docm format because macros can interfere with Copilot’s text extraction.

Copilot Summarizes Only Part of the Document

A partial summary usually indicates that some tracked changes were not fully resolved. Select the entire document by pressing Ctrl+A. Go to Review > Accept > Accept All Changes. Then go to Review > Reject > Reject All Changes. This second step ensures that any remaining revision markup is cleared. Save the document and try Copilot again.

Copilot Still Shows the Track-Changed Version in the Summary

If the summary includes strikethrough or underlined text, the document still contains revision markup that Copilot reads. Repeat the accept-all-changes step. Afterward, click the Track Changes button to confirm it is off. The button should be gray or not highlighted. Save the document, close it, reopen it, and then ask Copilot to summarize.

Copilot Summarization Behavior: Clean Document vs Track-Changed Document

Item	Clean Document	Track-Changed Document
Text stream	Single, unambiguous layer	Two overlapping layers (original + proposed)
Copilot summary output	Complete, accurate summary	Error, blank, or partial output
Fix required	None	Accept or reject all changes before summarizing
Effect on revision history	No revision history present	History is lost if changes are accepted in the same file
Recommended workflow	Summarize directly	Save a copy, accept changes, summarize the copy

Copilot in Word cannot summarize a document that contains active tracked changes because the revision markup creates a conflicting text stream. The fix is to accept or reject all changes in a copy of the document before running the summary command. Use the Compare tool to preserve the revision history separately. After you clear the markup, Copilot will generate a complete summary based on the final text. For documents with complex revision histories, always work on a duplicate to avoid losing the original markup.