Failed Mail Merged e-mails

The symptoms match a mail merge to email that completes in Word but fails to hand messages off correctly or deliver them from Outlook. Based on the provided information, use these checks and workarounds:

1. Confirm Outlook type and MAPI support

• Classic Outlook for Windows is required for reliable mail merge and MAPI-based sending.
• New Outlook for Windows is not MAPI-compliant and cannot be used for mail merge or for sending files directly from Office apps. If New Outlook is set as default, mail merge and “Share via email” scenarios can fail or behave inconsistently.
• Ensure Classic Outlook is installed and set as the default mail client before running the merge.

2. Avoid New Outlook as default mail client

• If New Outlook is currently the default, switch back to Classic Outlook and then re-run the mail merge.
• When New Outlook is default, Office apps can show MAPI failures or silently fail to send mail-merge messages.

3. Run the merge from Word with Outlook Classic

• Start Classic Outlook.
• In Word, use the Mailings tab and run the mail merge to email as usual, with Outlook Classic as the active/default mail client.
• If Outlook mail merge hangs or fails to initialize Word, try:
  • Starting Classic Outlook as Administrator once, then performing the mail merge, then restarting Outlook in normal mode.
  • Or starting Classic Outlook as Administrator, closing it, then starting it normally and running the mail merge. This can fix permissions/registry issues that block mail merge.

4. Use Word/Excel data source as an alternative

• If the Access-based merge is problematic, export the Access table to an Excel CSV or worksheet and use that as the data source in Word:
  • Export contacts/data from Access to Excel.
  • In Word, use Mailings → Select Recipients → Use an Existing List and point to the Excel file.
  • Complete the merge to email from Word with Outlook Classic.

5. Check for blocked messages in Classic Outlook

• If any previous attempts were made while New Outlook was in use, messages may be stuck in the Outbox of Classic Outlook and will send as soon as Classic Outlook is brought online.
• Before reconnecting, put Classic Outlook in Offline mode or disconnect from the internet if those old attempts should not be sent.

6. If sharing/attachments from Office show MAPI errors

• MAPI failures when sharing directly from Word/Excel/PowerPoint are another sign that New Outlook is default.
• Switching the default mail client to Classic Outlook resolves these MAPI failures and allows Office apps and mail merge to send via Outlook Classic.

After ensuring Classic Outlook is the default MAPI client and re-running the mail merge from Word (optionally using Excel instead of Access), the messages should be handed off correctly and appear in Sent Items, rather than failing with generic “cannot be reached” errors.

References:

• Mail merge in Microsoft Word does not work on a computer that is running Windows 7 or Windows Server 2008 R2
• Classic Outlook mail merge hangs trying to initialize Word
• Merge to Email problem - please help - Microsoft Q&A
• Mail Merge Emails not sent - Microsoft Q&A
• Mail merge to draft in outlook 365 - Microsoft Q&A
• I am unable to share my file either as a presentation or document type or pdf type by none of the microsoft office apps (Word, Excel, Powerpoint). It is continuously showing "Mapi Failure" and "Unable to Share" errors. What can I do? - Microsoft Q&A
• Office 365 apps insist on using Outlook Classic to share documents to email - Microsoft Q&A