Summary

OneNote syncs in the background without being asked, so when it stops there is rarely an obvious reason on screen. This article finds the notebook that is actually stuck and works through the five things that genuinely cause it: a storage location you can no longer reach, a section too large to upload, a stale sign-in, unresolved conflict pages, and a confused local copy.

Symptoms

• A yellow warning triangle or a red circle sits on a notebook name or a section tab in the navigation pane.
• Notes typed on your phone never appear on your laptop, or edits made on the laptop never reach the phone.
• A message reads We're having trouble syncing this section, or a notebook reports that it could not be synced.
• A page shows a coloured bar at the top warning about conflicting changes.
• One section refuses to sync while every other section in the same notebook updates normally.
• A colleague can see changes you cannot, or you are both looking at different versions of the same page.

In this guide

• 1. Tell Which Version of OneNote You Have
• 2. Check the Sync Status of Every Notebook
• 3. Force a Full Sync
• 4. Confirm You Can Still Reach Where the Notebook Is Stored
• 5. Cut Down a Section That Is Too Large
• 6. Find and Merge Conflict Pages
• 7. Sign Out, Then Close and Reopen the Notebook

Before You Start

• A Microsoft 365 work or school account, signed in to OneNote.
• The notebook stored in OneDrive, a SharePoint site, or a Teams site. OneNote does not sync notebooks saved to a local drive or a mapped network drive.
• An internet connection. No admin rights are needed for any step in this article.

Instructions

1. Tell Which Version of OneNote You Have

Two different Windows apps have carried the name OneNote, and their menus do not match. Thirty seconds here saves you hunting for a button that does not exist in your version.

1. Open OneNote and look at the far left of the ribbon along the top of the window.
2. If you see a File tab there, you have the OneNote desktop app. This is the app that used to be sold as OneNote 2016, and it is what Microsoft 365 installs today. Every step below applies to it directly.
3. If there is no ribbon and instead a Settings and more button (three dots) sits at the top right of the window, you are in the older OneNote for Windows 10 app. Its sync commands live behind a right-click on the notebook name in the left navigation pane rather than in a File menu.
4. To read the exact build, click File > Account in the desktop app. The version and build numbers appear on the right under About OneNote.

Note: Microsoft retired OneNote for Windows 10, and it no longer receives fixes. Moving to the OneNote desktop app resolves a whole class of sync problems on its own. Search for OneNote in the Start menu — the desktop app is often already installed alongside it. If it is not, tell IT: "Please install the OneNote desktop app from Microsoft 365 on my machine — I'm still on the retired OneNote for Windows 10."

2. Check the Sync Status of Every Notebook

Before changing anything, find out what is actually failing. OneNote shows one small warning icon for a problem that may sit three levels down.

1. In the desktop app, click the notebook name at the top of the left navigation pane. The list of open notebooks drops down.
2. Right-click the notebook you are worried about and select Notebook Sync Status. In OneNote for Windows 10, right-click the notebook in the navigation pane and select Sync Status instead.
3. The Shared Notebook Synchronization dialog opens. Every open notebook is listed with a green check mark for synced, a spinning icon for syncing in progress, or a yellow triangle with the error text printed beside it.
4. Read the error text next to the failing notebook and note the section name it mentions. That section is what the rest of this article works on.
5. Check the two options at the top of the dialog. Sync automatically whenever there are changes must be selected. If Sync manually is selected, OneNote only uploads when told to — which looks identical to a sync failure from the outside.

Verification: With the dialog still open, click Sync All. Healthy notebooks return to a green check mark within a few seconds, leaving only the genuine problem on screen.

3. Force a Full Sync

OneNote retries on its own schedule. These two shortcuts skip the wait.

1. Click anywhere inside the notebook you want to sync so that it is the active notebook.
2. Press Shift + F9 to sync that one notebook. The circular sync icon beside the notebook name spins and then clears.
3. Press F9 to sync every open notebook at once.
4. If the keyboard shortcuts do nothing, use the menu instead: click File > Info, click the Settings button beside the notebook name, and select Sync.
5. Watch the section tabs across the top. A section that is still stuck keeps its warning icon while the rest clear — that section is your problem.

Note: On most laptops the function-key row controls brightness and volume by default. If pressing F9 changes your screen brightness instead of syncing, hold Fn and press F9.

4. Confirm You Can Still Reach Where the Notebook Is Stored

A OneNote notebook is a folder living in OneDrive, a SharePoint site, or a Teams site. When your access to that location disappears, OneNote keeps showing you the local copy and keeps failing to upload — with an error that never mentions permissions.

1. Click File > Info. The full web address of each open notebook is printed under its name.
2. Select that address, copy it, paste it into your browser, and press Enter.
3. Read what the browser gives you:
   • The notebook opens in OneNote for the web. Your access is fine and the cause is elsewhere. Move on to the next step.
   • You need permission to access this site, or a request-access page. You have lost access to the SharePoint or Teams site holding the notebook. Click Request access on that page and state what you need it for.
   • The address contains -my.sharepoint.com/personal/ followed by a colleague's name. The notebook lives in that person's personal OneDrive rather than in shared storage. If they have left the company, their OneDrive is deleted once the retention period set by your organisation expires, and the notebook goes with it.
4. If the notebook sat in a departed colleague's OneDrive, send IT this, with the address you copied in step 1: "This OneNote notebook was stored in a departed colleague's OneDrive and I have lost access. Please restore it from retention and move it to a SharePoint site the team owns."

Tip: A notebook the whole team depends on belongs in a SharePoint or Teams site, not in one person's OneDrive. Moving it there removes this failure mode permanently — see Understanding Where Your Files Live — OneDrive vs. SharePoint vs. Teams.

5. Cut Down a Section That Is Too Large

OneNote uploads a section as one file. When a single section grows past what the service accepts in one piece, that section stops syncing while every other section in the same notebook carries on working. The cause is nearly always one enormous embedded file or a long run of pasted screenshots.

1. Click the failing section tab and scan the page list on the right for pages holding attachments or large images.
2. Open each candidate page. An embedded file appears as an icon with the file name beneath it; a pasted screenshot appears as a full-width image.
3. Right-click an embedded file and select Cut. Save the file into OneDrive or the team's SharePoint site, then paste a link to it on the page. The page keeps the reference and the section loses the weight.
4. Click any pasted image you no longer need and press Delete.
5. If the section is long rather than heavy, split it. Right-click a page in the page list, select Move or Copy, choose a new section in the same notebook, and click Move.
6. Press Shift + F9 and watch the section tab. The warning icon clears once the lighter section finishes uploading.

Note: OneNote reports this as a message that the section is full or cannot be saved because it is too large. Both wordings mean the same thing, and both are fixed by taking weight out of that one section rather than out of the notebook as a whole.

6. Find and Merge Conflict Pages

When two devices edit the same paragraph before either has synced, OneNote does not pick a winner. It keeps both versions and tells you — quietly enough that people miss it for weeks.

1. Look at the top of the affected page for a coloured information bar reading This page contains conflicting changes. Click the bar to open the conflicting version.
2. Scan the page list on the right for a duplicate page whose title is shown in red and carries a date and the name of the computer that made the change. That is the conflict copy.
3. Open the conflict copy. The text that differs from the original is highlighted, so you can see exactly what each version claims.
4. Copy anything worth keeping out of the conflict copy and into the original page.
5. Right-click the conflict page and select Delete once you have taken what you need. The information bar disappears from the original page.
6. Press Shift + F9. With the conflict cleared, the section syncs normally.

Note: Earlier versions of a page are kept under History > Page Versions in the desktop app, each labelled with a date and an author, and deleted pages sit in History > Notebook Recycle Bin for 60 days. If you remove the wrong version, that is where to get it back.

7. Sign Out, Then Close and Reopen the Notebook

Two resets, in order. The first refreshes the credentials OneNote uses to talk to OneDrive. The second rebuilds the local copy of the notebook and is the one that clears the most stubborn cases.

First, sign out and back in:

1. Click File > Account.
2. Under User Information, click Sign out. OneNote closes your notebooks and returns to a signed-out state.
3. Close OneNote completely, then reopen it.
4. Click Sign in, enter your work email address and password, and complete any verification prompt. Your notebooks reopen and syncing restarts.

Note: Open Notebook Sync Status before you sign out and confirm nothing is listed as waiting to upload. Unsynced edits live only in the local copy on that one computer, and a sign-out is the wrong moment to discover them.

Then, close and reopen the notebook:

5. Click the notebook name at the top of the left navigation pane to drop down the notebook list.
6. Right-click the notebook that will not sync and select Close This Notebook. It disappears from the list. Nothing is deleted — the notebook still exists in OneDrive or SharePoint.
7. Click File > Open, then select the notebook under Recent Notebooks. If it is not listed, click Browse and pick it from your OneDrive or SharePoint site.
8. OneNote downloads a fresh copy of every section. On a large notebook this takes a few minutes, and the section tabs fill in as they arrive.
9. Open Notebook Sync Status once more. Every notebook now shows a green check mark.

Verification: Type a single word on any page from your phone. It appears on your laptop within about 30 seconds. Testing in both directions is what proves the sync is genuinely fixed rather than working one way.

Troubleshooting

WARNING

Open Notebook Sync Status and confirm nothing is waiting to upload before you sign out, close a notebook, or let anyone clear the OneNote cache on your machine. Edits that have not synced exist only in the local copy on that one computer, and a reset performed before they upload discards them. If a section refuses to sync at all, select its contents, paste them into a page in a different notebook, and sort out the sync problem afterwards.

Symptom / Error	Potential Cause	Solution
"We're having trouble syncing this section"	Section too large to upload	Take the largest embedded file or pasted images out of that one section (Step 5), then press Shift + F9.
Every notebook syncs except one	Access to its storage location lost	Paste the notebook address from File > Info into a browser (Step 4). A permission page means the site is no longer shared with you.
Edits from your phone never arrive on the laptop	Notebook set to sync manually	Open Notebook Sync Status and select Sync automatically whenever there are changes (Step 2).
A section sits under "Misplaced Sections"	OneNote found a section it cannot place	Right-click the section tab, select Move or Copy, and choose the notebook it belongs to.
The same page keeps duplicating itself	Conflict pages never resolved	Merge the conflict copies into the original and delete them (Step 6).
Nothing syncs after a password change	Stale sign-in on the device	Sign out under File > Account, restart OneNote, and sign back in (Step 7).

Related Articles

• How to Use OneNote for Note-Taking and Organization
• How to Fix OneDrive Sync Problems — Pending, Stuck, or Files Not Uploading
• Understanding Where Your Files Live — OneDrive vs. SharePoint vs. Teams
• How to Restore a Previous Version of a File in OneDrive

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