How to Fix OneNote Sync Failure Error Code 0xE00009C8

OneNote sync failure error code: 0xE00009C8 typically occurs due to difficulties in syncing notebooks, preventing the data from being updated on all devices. When this error occurs, it means the OneNote app is unable to communicate with the cloud service, likely due to corrupted sync data or connectivity issues.

The most common cause of this issue is usually corrupted cache data stored locally, which interrupts the syncing process. Other causes can include temporary authentication issues, an outdated OneNote app, or a weak internet connection.

By following this guide, you will be able to resolve the syncing issues and ensure that all notebooks stay up-to-date across devices. With the causes outlined, let’s look at the solutions to this issue.

1. Manually Sync the Notebook

Manually syncing the notebook forces the application to establish a fresh connection with the cloud server to synchronize data across all devices. This process bypasses sync errors and updates both local and cloud data, enabling other devices to fetch the updated data from the server. This step is particularly useful when automatic syncing is not functioning properly.

1. From Home, click File at the top.
2. Click View Sync Status and then click Sync Now or Sync All at the top right.
   
3. Once done, check if this resolved the error.

2. Check for Server Issues

Checking the server status can help determine whether the issue lies on Microsoft’s side. If Microsoft is experiencing any service outages, it may prevent the synchronization process and display error messages.

To check the server status, simply visit portal.office.com/servicestatus to ensure that the OneDrive and OneNote servers are functioning properly.

Additionally, you can visit the Microsoft Community forums to see if other users are encountering the same issue. If the servers are down or undergoing maintenance, you can wait for them to stabilize, which should resolve the sync failure without any further action required on your part.

3. Sign Out and Back Into OneNote

Signing out and signing back in will refresh the authentication tokens and re-establish the connection with the cloud service such as OneDrive. This will resolve issues related to expired authentication tokens that might be preventing the syncing process and displaying the error message.

By signing out and signing back in, you ensure that you have updated authentication information that often resolves the OneNote app syncing issues.

1. From the OneNote app, click on your profile icon and select Sign Out.
   
2. Once you are signed out, sign in again with your credentials and see if the error is resolved or not.

4. Clear OneNote Cache

The cache stores temporary files to enhance application performance and reduce loading times. However, over time, these cache files can become corrupted, which may prevent the application from functioning properly.

By clearing the temporary cache files, you allow the OneNote application to create a fresh cache, which should restore the syncing process. Therefore, try clearing the OneNote cache to see if this resolves the issue.

Before following the steps, make sure the OneNote app is closed.

1. Press Win + R keys simultaneously to open the Run program.
2. Then, enter the following destination path of the OneNote cache and hit Enter to navigate.

   C:\Users\YourUsername\AppData\Local\Microsoft\OneNote\16.0\cache

   

3. Replace YourUsername with your actual username and 16.0 with the version of the OneNote application.
4. Here, press Ctrl + A to select all the files and press the Delete key to remove all the cache files.
   
5. Once done, relaunch the application to see if the problem is resolved or not.

In case the error persists, you can try reinstalling the OneNote application, which should restore any corrupted files that might be causing the issue.