Fix Word Co-Author Sync Pause When Comments Exceed Specific Threshold

You are editing a Word document with a colleague. Both of you add comments and make changes. Suddenly, the co-author sync indicator shows a pause. You see a message that sync has stopped because the number of comments exceeds a threshold. This happens because Word has a built-in limit on the total number of comments and replies that can be synced in real time. When you exceed that limit, Word pauses sync to protect document stability. This article explains why the sync pause occurs and provides specific steps to reduce the comment count and restore collaboration.

Why Word Pauses Sync When Comments Exceed a Specific Threshold

Word for Microsoft 365 and Word for the web use a real-time collaboration engine. This engine syncs edits, comments, and replies between all co-authors. To keep the document responsive and prevent data corruption, the engine enforces a hard limit on the total number of comment threads plus replies. The exact threshold varies by version, but it is typically around 500 to 700 individual comment items (threads plus replies). When the count reaches that limit, Word pauses sync and displays a yellow bar: “Sync paused because the document has reached the maximum number of comments.”

This limit exists because each comment and reply is stored as a separate XML node in the document file. A very large number of nodes increases the file size and slows down the sync engine. Word pauses sync to prevent the document from becoming unresponsive or corrupting during simultaneous edits. The pause is temporary. Once you reduce the comment count below the threshold, sync resumes automatically within a few seconds.

Steps to Reduce Comments and Restore Sync

Follow these steps in the order shown. Each step reduces the comment count. After each step, wait 10 seconds to see if the yellow sync bar disappears. If sync resumes, you do not need to proceed further.

1. Open the Comments pane and sort by status
   Go to Review > Show Comments. The Comments pane opens on the right. Click the filter icon (funnel) and select Resolved or Done. This shows only resolved comments that can be deleted safely. Right-click a resolved comment thread and choose Delete Thread. Delete all resolved threads first because they are no longer needed for collaboration.
2. Delete old or irrelevant comment threads
   In the same Comments pane, review unresolved threads. If a thread contains outdated feedback or a question that has been answered, delete it. Right-click the thread and select Delete Thread. Each deletion removes one thread plus all its replies, reducing the total count by several items at once.
3. Use Inspect Document to find hidden comments
   Go to File > Info > Manage Document > Check for Issues > Inspect Document. In the dialog, ensure Comments, Revisions, Versions, and Annotations is checked. Click Inspect. If the inspection finds comments, click Remove All next to that section. This deletes all comments in the document, including any that are hidden in headers, footers, or text boxes.
4. Save the document and close the Comments pane
   Press Ctrl+S to save. Then close the Comments pane by clicking the X in the top-right corner of the pane. Wait 10 seconds. The yellow sync bar should disappear and the sync indicator should show a green checkmark or a syncing icon.
5. If sync does not resume, save a copy and remove all comments
   Go to File > Save As and save a copy of the document with a new name, such as “Report_Clean.docx.” In the copy, go to Review > Delete > Delete All Comments in Document. Save the copy. Share this copy with your co-authors. Now you can add new comments that stay below the threshold.

If Sync Still Does Not Resume After Reducing Comments

“Sync paused” message remains even after deleting all comments

Word may still show the paused bar if the document contains a high number of tracked changes. Tracked changes also count toward the internal sync limit. Go to Review > Accept > Accept All Changes and Stop Tracking. Then save and wait. If the bar remains, close Word completely, reopen the document, and wait 30 seconds.

Co-authors cannot see the reduced comments

Each co-author must close and reopen the document to see the updated comment count. Ask all collaborators to save their work, close the file, and reopen it from the shared location (OneDrive or SharePoint). Sync resumes for all users after the document reloads.

Comments keep reappearing after deletion

This happens when the document is stored in a location with versioning enabled and a co-author has an unsaved local copy. Ask all co-authors to save and close the document. Then go to File > Info > Version History and delete any older versions that contain the excess comments. After that, repeat the deletion steps.

Comment Threshold Limits by Word Version

Word Version	Maximum Comments (Threads + Replies)	Sync Behavior at Limit
Word for Microsoft 365 (Desktop)	500 items	Pauses sync, shows yellow bar, allows editing without sync
Word for the web	700 items	Pauses sync, shows yellow bar, read-only until count reduced
Word for Mac (Microsoft 365)	500 items	Pauses sync, shows yellow bar, editing allowed
Word 2021, 2019 (perpetual)	No real-time co-author sync, no limit applies	N/A

The 500-item limit applies to the total of all comment threads plus all replies within those threads. A single thread with 10 replies counts as 11 items. If you regularly work with heavily commented documents, consider using a separate review document or archiving resolved comments in a text file outside Word.

You can now reduce the comment count in any Word document to restore co-author sync. Start by deleting resolved threads and using Inspect Document to remove hidden comments. If the problem recurs, save a clean copy and add only essential comments. To prevent future pauses, ask your team to resolve and delete comments weekly. Use the Review > Next Comment and Previous Comment buttons to quickly scan through threads before deleting them.