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How to Fix OneNote Running Slowly and Using High CPU on Mac
Question details
The user is experiencing slow performance, excessively high CPU usage, high memory pressure, and loud fan noise when using Microsoft OneNote.
- Product
- Microsoft OneNote
- Device & OS
- macOS
- Scenario
- Using the OneNote desktop application for note-taking and synchronization, especially with notebooks containing large PDF printouts.
- Observed behavior
- OneNote runs extremely slowly, memory usage spikes up to 16 GB turning memory pressure red, CPU usage reaches around 165%, and the Mac's cooling fans run loudly.
Before making changes to your notebooks, open the Activity Monitor on your Mac to confirm that Microsoft OneNote is the specific application causing the high CPU and memory usage.
Use OneNote for the Web as a Workaround
Switching to the web version of OneNote bypasses the desktop application's excessive resource drain while keeping your notes synchronized across devices.
Many Mac users report that when the desktop client struggles with memory leaks or high CPU usage, the online version remains stable and responsive.
Launch Safari, Chrome, or your preferred web browser on your Mac.
Navigate to the official Microsoft OneNote website and sign in with your Microsoft account credentials.
Open your notebooks directly in the browser interface. Any edits you make will synchronize immediately with your other devices, such as an iPad or iPhone.
Manage Large PDF Printouts and Divide Notebooks
Large PDF files inserted directly as printouts are a common trigger for sync issues and high memory pressure. Removing them or splitting the notebook can help restore performance.
Test in Safe Mode and Reinstall OneNote
If organizing your notebooks does not resolve the performance drop, testing your Mac in Safe Mode can rule out background interference, and reinstalling can fix corrupted app files.
Looking for a Lightweight Note-Taking Solution? Try WPS Office
If Microsoft OneNote continues to drain your Mac's CPU and memory, consider switching to WPS Office. It provides a fast, lightweight, and free alternative with full support for Microsoft Office formats, ensuring your device runs smoothly without excessive fan noise or overheating.
- 1. Download WPS Office: Visit the official WPS website and download the macOS version of WPS Office.
- 2. Install the Software: Open the downloaded installer package and drag the WPS Office icon into your Applications folder.
- 3. Create Lightweight Documents: Launch WPS Docs to start typing, organizing your notes, and managing PDFs without excessive system resource drain.
Frequently Asked Questions
Why is OneNote using so much memory and CPU on my Mac?
High resource usage in OneNote is typically caused by the application struggling to synchronize large files, such as massive PDF printouts, or a corrupted notebook that constantly attempts to resolve background sync errors.
How can I monitor the exact CPU and memory usage of OneNote on macOS?
You can monitor this by opening 'Activity Monitor' from your Mac's Utilities folder. Click on the 'CPU' or 'Memory' tabs and locate 'Microsoft OneNote' in the list to view its real-time resource consumption.
Will dividing my OneNote notebooks definitely fix the memory pressure issue?
Dividing notebooks helps reduce the continuous load required for synchronization. However, if the underlying issue is a highly corrupted file or a single excessively large PDF printout, the problem might persist until those specific elements are deleted.
Does reinstalling OneNote delete my notes?
No, as long as your notebooks are fully synchronized to OneDrive. Reinstalling the app simply replaces the local software files. Once you log back in, your notes will download from the cloud.
