MAPI failure

This usually happens because Word’s Share > Email feature depends on a MAPI-compliant default mail app. The supported fix is to use Classic Outlook, not New Outlook.

Steps to fix it:

1. Check which Outlook is set as default
   • If New Outlook is the default mail app, Word sharing can fail with MAPI errors.
   • Set Classic Outlook as the default email application instead.
2. If Outlook is installed, make sure it is the default email app
   • Office can send a document by email only when Outlook is installed as part of Microsoft 365 and set as the default email app.
3. Try sending from Word again
   • In Word, go to File > Share.
   • Choose Attach a copy instead to attach the document or a PDF.
   • Enter recipients and send.
4. If the file is too large and nothing happens
   • Check the Windows Application event log for Event ID 27.
   • If present, the attachment exceeded the Exchange size limit.
   • Fix by either:
     • compressing the file into a ZIP,
     • putting the file on a share or web host and emailing a link,
     • or asking the Exchange administrator to increase the attachment limit.
5. If the issue continues
   • Repair Office, then test again.

If Classic Outlook is not available, the practical workaround is to open the mail app manually, create a new message, and attach the Word document directly.

References:

• Email a document from Microsoft Office
• Event ID 27 when sending attachments outside of Outlook fails
• Can't send or receive email in Outlook and "Metered Connection Warning" is triggered
• Word couldn't send mail because of MAPI failure " Unspecified error" - Microsoft Q&A
• I have an issue with sharing my word docx as pdf through the share option within word, it says that can't share the file due to "MAPI failure" how should i fix this? - Microsoft Q&A
• MAILTO Protocol in default Apps not working for Outlook - Microsoft Q&A