MAILTO Protocol in default Apps not working for Outlook

Anonymous
2025-01-09T09:02:43+00:00

To whom it may concern. Our customer is using Windows 11 with Microsoft 365 Office Current Channel v2411 build 18227.201162.

When we try to send a Microsoft Word document by selecting > Share > Email send as Attachment

I get the message - "Either there is no default mail. Please run Microsoft Outlook and set it as the default mail client".

Outlook is already set as a default client in the default Apps option and the default applications by the protocol are already set as MAILTO Protocol in the default Apps option to Outlook (new). Please assist.

Microsoft 365 and Office | Word | For business | Windows

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Doug Robbins - MVP - Office Apps and Services 323.6K Reputation points MVP Volunteer Moderator
2025-01-13T07:24:51+00:00

The “New Outlook is just a re-badged version of Windows Mail and like its predecessor, it is not MAPI compliant and cannot be used to send messages from any of the other Office applications (Access, Excel, Word).

The Outlook Product Team have advised that there are no plans to add MAPI compliance to the "New Outlook", which I suspect is because it is not possible to do so.

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  1. Stefan Blom 351.3K Reputation points MVP Volunteer Moderator
    2025-01-09T09:59:12+00:00

    You have to set the classic Outlook as the default for e-mails instead of the new Outlook.

    The new Outlook won't work, as you have noticed, because it isn't MAPI-compliant.

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  2. Suzanne S Barnhill 279.1K Reputation points MVP Volunteer Moderator
    2025-01-11T02:00:39+00:00

    New Outlook is not MAPI-compliant and cannot be used to send mail from within Word. You have to use Classic Outlook for this.

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  3. Stefan Blom 351.3K Reputation points MVP Volunteer Moderator
    2025-01-10T15:21:25+00:00

    Thanks for the update.

    For some reason, Windows doesn't recognize Outlook as the default for the affected user(s).

    In your very first message you say that Outlook (new) is the default for the Mailto protocol. At a guess, that is part of the problem, but I'm not sure.

    Maybe the Windows forum would be a better place to ask, or the Outlook forum.

    EDIT: See Diane's reply in this thread.

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  4. Diane Poremsky MVP 17,526 Reputation points MVP Volunteer Moderator
    2025-01-10T15:04:45+00:00

    Delete groupwise from the default value. Or tell the user to save the doc and open an email, then use the Include > Insert file button. The newly saved file should be first on the list.

    You'll normally only have one of the reg keys - so its normal that you don't have the local machine one.

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