Office for Mac Issues

Fix OneNote Sync Problems and High CPU/Memory Usage on Mac

Camila Milosovich Oct 10, 2026 868 views

Question details

Users are experiencing severe Mac slowdowns, memory warnings, and sync failures with specific OneNote pages or folders, which persist even after reinstalling or clearing the cache.

How to Fix OneNote Sync Problems and High Mac Performance Usage

Product: Microsoft OneNote
Device & OS: macOS Sonoma 14.0
Scenario: Attempting to sync specific OneNote pages while the application consumes excessive system memory and causes severe Mac lag.
Observed behavior: OneNote causes the Mac to slow down significantly, triggers memory warnings, and fails to sync certain notes to the web version.

Before you start

Before proceeding, log into OneNote for the Web to check which pages have successfully synced online. Immediately copy and paste any unsynced text from your Mac into a safe location like Apple Notes or TextEdit to prevent permanent data loss.

Solution 1Recommended

Test with a New macOS User Profile

Creating a new user profile helps determine if the high resource usage and sync errors are caused by corrupted local user settings or background conflicts.

If OneNote is lagging severely, your local user preferences or macOS cache for that specific profile might be corrupted. Testing in a fresh environment isolates the issue.

Open System Settings

Click the Apple menu in the top-left corner of your screen and select 'System Settings' (or 'System Preferences' on older macOS versions).

Add a New User

Navigate to 'Users & Groups', click 'Add Account' (or the '+' button), and enter your administrator password when prompted.

Create Account and Log In

Set up a new Standard or Administrator account. Once created, log out of your current session and log into the newly created macOS profile.

Test OneNote Sync

Open OneNote in the new user profile, sign into your Microsoft account, and check if the severe lag and syncing issues persist.

Solution 2

Isolate and Remove Problematic Pages

Since the sync failure and memory loop are often tied to just one or two specific pages, isolating and removing them can restore normal performance.

Free Microsoft Office alternative

Experience Smooth and Lightweight Note-Taking with WPS Office

If OneNote continues to drain your Mac's memory and fail at syncing, consider switching to WPS Office. It provides a lightweight, highly compatible alternative for document management and note-taking without slowing down your macOS system.

1. Download WPS Office: Visit the official WPS website and download the free installation package tailored for macOS.
2. Install and Launch: Follow the standard Mac installation prompts to install the software, then open WPS Writer.
3. Create and Save Notes: Start a new document, paste your recovered notes, and save them securely to WPS Cloud for instant syncing across devices.

Uses significantly less RAM and CPU, keeping your Mac running fast and responsive.Fully compatible with Microsoft Word, Excel, and PowerPoint formats.Built-in WPS Cloud sync provides a reliable and easy way to manage notes across all your devices.Clean, intuitive interface familiar to Office users for a seamless transition.

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Frequently Asked Questions

Why is OneNote using so much memory on my Mac?

High memory usage in OneNote for Mac is typically caused by continuous background syncing loops, corrupted cache files, or excessively large notebooks containing heavy media files that the app struggles to upload.

Will reinstalling OneNote fix the sync issue?

Reinstalling the app can help if the core application files are corrupted. However, it often does not resolve sync failures if the problem is tied to a specific corrupted page, local macOS user profile settings, or server-side restrictions.

Where does OneNote store local backup files on Mac?

Unlike the Windows version, OneNote for Mac does not have a local automatic backup folder feature. It relies entirely on real-time OneDrive syncing, which is why copying unsynced text manually is crucial before troubleshooting.

How do I safely clear the OneNote cache on a Mac?

You can clear the cache by fully closing OneNote, opening Finder, pressing Command+Shift+G, navigating to '~/Library/Containers/', and deleting the 'com.microsoft.onenote.mac' folder. Be aware that doing this will permanently delete any unsynced offline changes.

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