How to fix
OneNote error code 0xE00009C8
on Windows

Hi. After a reboot today, I restarted my laptop and can no longer sync my OneNote files. The error message says "OneNote can't sync your notes right now. We'll keep trying. (Error code: 0xE00009C8 bb0ur)." What is this and how can I fix it?

Error code 0xE00009C8 usually implies an error related to synchronizing notebooks with devices. This error prevents any update from being pushed out to the cloud, which may link changes made in OneNote so that these are reflected upon opening on other devices or platforms. Users are normally facing this error stating that OneNote has failed to connect properly to the cloud service because of corrupted cache files or network issues.

The most common causes of the 0xE00009C8 error include corrupted cache files, which can interrupt the syncing process. Over time, OneNote's cache files may become outdated or damaged, blocking the app's ability to sync properly. Also, issues in network connectivity, like unstable internet or restrictions from the firewall, will prevent the app from communicating with the cloud servers, thus causing this error.

Other possible causes may include issues with authentication. If OneNote cannot authenticate users correctly, it will not be able to connect to the server properly. This may happen in case the application's session has expired or there is a momentary glitch affecting Microsoft's services. Apparently, the reason for receiving the 0xE00009C8 error also includes using an older version of OneNote that cannot be fully compatible with the updated protocols that the server must be using.

The few who have encountered the 0xE00009C8 error have gone ahead and troubleshot their network to see whether OneNote is updated or even cleared up the application's cache in order to get rid of corrupted files. Sometimes it's fixed by manually syncing the notebook-most times just by signing out and reconnecting to the app-refreshing the connection that could be causing issues.

When that does not work, it could mean that there are deeper system-level conflicts or corrupted OneNote files in which case earmarking the use of a PC repair tool such as [d1] may be apt for automatic detection and fixation of these problems.

Fix 1. Update OneNote

An outdated version of OneNote may not be compatible with Microsoft’s updated server protocols, leading to sync errors. Ensuring your app is up to date can resolve compatibility issues.

• Open the Microsoft Store and search for OneNote.
• Check if an update is available and install it.
• Restart your computer and relaunch OneNote.

Fix 2. Manually sync the notebook

Manually syncing the notebook can help OneNote establish a fresh connection with the cloud server, forcing an update that may bypass the error.

• Open OneNote and click on the notebook you’re having issues with.
• Go to the File menu and select View Sync Status.
• Click Sync Now or Sync All to initiate a manual sync.

Fix 3. Check your network connection

Network problems, such as unstable Wi-Fi or restrictions set by a firewall, can prevent OneNote from syncing properly.

Windows 11

• Type Troubleshoot in Windows search and hit Enter.
• Select Other troubleshooters.
• Find Network & Internet from the list and select Run.
• Wait till the scan is finished - you will be provided with potential causes so you can proceed with fixes.

Windows 10

• Right-click on Start and pick Settings.
• Go to the Network & Internet section.
• On the right side, find the Advanced network settings section.
• Click Network troubleshooter and wait.
• The fixes will be automatically applied.

Fix 4. Clear the OneNote cache

Corrupted cache files can disrupt the syncing process, causing error code 0xE00009C8. Clearing the cache can remove these corrupted files and allow OneNote to create a fresh, functioning cache.

• Close OneNote completely.
• Navigate to the following location:
  C:\Users\YourUsername\AppData\Local\Microsoft\OneNote\16.0\cache (replace with your username and OneNote version).
• Delete all files in this folder.
• Restart OneNote and try syncing again.

Fix 5. Sign out and sign back into OneNote

Refreshing your login credentials can help resolve authentication issues that might be causing the sync error.

• Click on your profile icon in OneNote and select Sign Out.
• Restart OneNote and sign in again with your Microsoft account.
• Try syncing the notebook after signing back in.

Fix 6. Verify server status

Sometimes, OneNote sync errors occur due to issues with Microsoft’s servers rather than your local system. Checking the server status can help you identify if the problem is temporary.

• Visit Microsoft’s service status page to check if OneDrive and OneNote servers are experiencing outages.
• If there is a server issue, wait until it’s resolved, then attempt to sync again.

Fix 7. Repair or reinstall OneNote

If OneNote continues to show error code 0xE00009C8, it may be due to a corrupted installation. Repairing or reinstalling the app can resolve deeper issues that clearing the cache or resetting settings might not fix.

• Type Control Panel in Windows search and press Enter.
• Select Programs and Features.
• Find Microsoft Office in the list, right-click, and choose Online repair.
• Follow the on-screen instructions to complete the repair process.
• If repairing doesn’t work, uninstall OneNote, then reinstall it from the Microsoft Store.
• Restart your device and check if the error is resolved.