Office Apps Crashing

Fix OneNote 2019 Crashing During Notebook Synchronization

Rana Garcia Oct 13, 2026 868 views

Question details

The user needs to fix an issue where OneNote repeatedly crashes when attempting to synchronize notebooks.

Fix OneNote 2019 Crashing During Notebook Synchronization

Product: Microsoft OneNote 2019
Device & OS: Windows
Scenario: Synchronizing notebooks across multiple devices and updating content.
Observed behavior: OneNote crashes and reports an access violation in ONMain.dll during sync. The issue persists despite repairing the application, clearing the cache, starting in Safe Mode, and migrating to new notebooks.

Before you start

Verify that your internet connection is stable and manually copy any newly added, unsynchronized notes into a local text file to prevent data loss during troubleshooting.

Solution 1Recommended

Isolate the Issue and Test Alternative Versions

Determine if the crash is tied to a specific notebook or system environment, and try using the built-in Windows 10 app as a workaround.

Crashes involving ONMain.dll can be triggered by corrupted notebook data or conflicts within the local Windows user profile. Isolating the exact trigger can help determine if the issue is localized to a specific file or spans the entire Office installation.

Create a completely new notebook

Open OneNote and click File > New to create a blank notebook. Copy a small amount of data into it and attempt to sync to see if the crash still occurs.

Test on a different Windows user profile

Create a new local administrator account in Windows Settings > Accounts. Log into the new profile, launch OneNote, and test the synchronization process.

Update Windows and Microsoft Office

Go to Windows Settings > Update & Security to check for the latest cumulative updates. In OneNote, navigate to File > Account > Update Options and click Update Now.

Install OneNote for Windows 10

If permitted on your device, open the Microsoft Store, search for 'OneNote for Windows 10', install it, and check if it syncs your notebooks without crashing.

Isolate the Issue and Test Alternative Versions

OneNote Versions: OneNote 2019 (desktop) and OneNote for Windows 10 are separate applications. If the desktop version fails, the Windows 10 app often remains stable.

Solution 2

Submit a Service Request via Microsoft 365 Admin Center

Escalate the issue to Microsoft Support to collect diagnostic logs and investigate the ONMain.dll access violation at the administrative level.

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Frequently Asked Questions

Why does ONMain.dll cause OneNote to crash during synchronization?

ONMain.dll is a core module required for OneNote's functionality. When it encounters an access violation, it typically means the application is trying to read or write to a restricted memory address. This can be caused by corrupted notebook cache files, conflicting updates, or damaged Office installation files.

Will I lose my notes if OneNote crashes during synchronization?

Any notes that have not successfully synced to the cloud server might be at risk if the local cache becomes corrupted. It is highly recommended to manually copy any unsynced text to a local Word document or Notepad file before attempting complex repairs.

How do I know if the crash is caused by a specific notebook?

You can determine this by creating a brand-new, empty notebook and adding a small amount of text. If the new notebook synchronizes successfully without crashing the application, the issue is likely isolated to the corrupted sections or formatting of your original notebook.

Can I use OneNote for Windows 10 if I don't have access to the Microsoft Store?

If your device is managed by an organization and the Microsoft Store is disabled, you will not be able to download OneNote for Windows 10 directly. In this case, you must contact your IT administrator to push the application to your device or resolve the desktop version crash via a support ticket.

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