Office Settings & Configuration

How to Set Outlook as the Default Email App for OneNote PDF Sharing

Algirdas Jasaitis Sep 28, 2026 869 views

Question details

The user needs to configure their system so that OneNote automatically opens Microsoft Outlook, rather than Thunderbird or other clients, when sharing a page as a PDF via email.

How to Set Outlook as the Default Email App for OneNote PDF Sharing

Product: Microsoft OneNote and Outlook
Device & OS: Windows 10
Scenario: Sharing a OneNote page as a PDF using the 'Email Copy of Page' functionality.
Observed behavior: OneNote launches Thunderbird instead of Outlook. Furthermore, setting 'New Outlook' as the default mail application fails to trigger correctly because it lacks MAPI support.

Before you start

Verify that you have Classic Outlook installed on your computer, as the 'New Outlook' application does not support the necessary MAPI protocols required to send emails directly from Office applications.

Solution 1Recommended

Configure Classic Outlook as the Windows Default Mail App

Use this solution to force Windows to route all email and MAPI sharing requests from applications like OneNote to Classic Outlook.

Windows 10 uses default app associations to determine which program handles email requests. Since New Outlook is not MAPI-compliant, you must specifically assign Classic Outlook as the handler for both email and protocol links to resolve the OneNote sharing issue.

Open Windows Settings

Click the Start menu on your Windows 10 taskbar and select the gear icon to open Settings. Alternatively, press the Windows key + I.

Navigate to Default Apps

Click on 'Apps' from the main Settings menu, then select 'Default apps' from the left-hand sidebar.

Set the Email Default

Under the 'Email' section, click on your current default application (e.g., Thunderbird or Mail) and select 'Outlook' (the Classic desktop version) from the list.

Verify Protocol Associations

Scroll down to the bottom of the Default apps page and click 'Choose default apps by protocol'. Scroll down to 'MAILTO' and ensure it is also set to Classic Outlook.

Configure Classic Outlook as the Windows Default Mail App

Settings Applied Successfully: Once configured, restart OneNote. The 'Email Copy of Page' function should now launch Classic Outlook with your PDF attached.

Solution 2

Switch from New Outlook to Classic Outlook

If you are currently using the 'New Outlook' toggle, you must revert to Classic Outlook to regain the MAPI capabilities required by OneNote.

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Frequently Asked Questions

Why does OneNote fail to use New Outlook for sharing PDFs?

New Outlook is not MAPI-compliant. MAPI (Messaging Application Programming Interface) is the protocol Microsoft Office applications use to communicate with email clients and attach files directly. Because New Outlook lacks this, you must use Classic Outlook for direct sharing.

Can I keep Thunderbird as my default for everything except OneNote?

Windows generally handles email defaults at the system level. You cannot easily set OneNote to use Outlook while keeping Thunderbird as the system-wide mail default without specialized third-party routing tools or manual registry edits.

Why do my PDF printing options look different in OneNote?

OneNote for Windows 10 and OneNote for Microsoft 365 are different applications. OneNote for Windows 10 uses the simplified modern Windows print dialog, while OneNote for Microsoft 365 relies on the traditional, full-featured desktop printer selection dialog.

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