Attachment Issues

How to Fix Unable to Send Word Document Through Outlook

WPS Editor Sep 27, 2026 869 views

Question details

The user encounters an error when attempting to send a Microsoft Word document directly as an email attachment via Microsoft Outlook.

Unable to Send a Word Document Through Outlook

Product: Microsoft Word / Microsoft Outlook
Device & OS: not provided
Scenario: Using the in-app sharing feature in Microsoft Word to send the active document as an email attachment.
Observed behavior: Word displays an unspecified error and fails to attach the document, a problem that frequently occurs when the user has switched to the 'New Outlook' interface.

Before you start

Save your Word document locally to prevent any data loss, and verify whether you are currently using the Classic Outlook or New Outlook interface on your computer.

Solution 1Recommended

Switch from New Outlook to Classic Outlook

Revert to Classic Outlook, which fully supports the MAPI protocol required by Word to automatically attach documents to emails.

The 'New Outlook' application currently lacks full MAPI (Messaging Application Programming Interface) compliance. Because Microsoft Word relies on MAPI to communicate with your email client and generate attachments automatically, this missing integration causes an unspecified error.

Open New Outlook

Launch the New Outlook application on your desktop.

Locate the toggle switch

Look in the top-right corner of the New Outlook window for a toggle switch labeled 'New Outlook'.

Turn off New Outlook

Click the toggle switch to turn it to the 'Off' position. A prompt may appear asking for feedback; you can provide it or skip.

Restart into Classic Outlook

Allow the application to close and automatically relaunch the Classic Outlook interface.

Retry sending the document

Open your Microsoft Word document and attempt to send it as an email attachment again.

Switch from New Outlook to Classic Outlook

Integration Restored: Classic Outlook is fully MAPI-compliant, ensuring that features like 'Share as Attachment' in Microsoft Office applications work seamlessly.

Solution 2

Attach the Document Manually

Bypass the automated integration by saving the document and attaching it manually within New Outlook.

Free Microsoft Office alternative

Try WPS Office for Seamless Document Management

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1. Download the software: Visit the official WPS Office website and click the free download button for your operating system.
2. Install WPS Office: Run the downloaded installer and follow the quick on-screen instructions.
3. Start sharing seamlessly: Open WPS Writer to create, edit, and easily share your documents without complicated integration errors.

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Frequently Asked Questions

What does it mean that New Outlook is not MAPI-compliant?

MAPI (Messaging Application Programming Interface) is a protocol used by Windows applications to communicate with your email client. Because New Outlook currently does not fully support this protocol, desktop apps like Word cannot automatically create and attach files to a new email.

Can I still use New Outlook and send Word documents?

Yes. While you cannot use the 'Email as Attachment' button directly inside Word, you can still save the Word document to your computer, open New Outlook, create a new email, and attach the file manually.

Will Microsoft fix the attachment issue in New Outlook?

Microsoft is actively developing New Outlook and is expected to improve MAPI support in future updates. Until full support is implemented, switching to Classic Outlook or attaching files manually are the best workarounds.

Outlook & Email Problems