Mail Merge in New Outlook: Does It Work?

Word mail merge doesn't work in New Outlook. Here's why, what New Outlook's built-in mail merge can do, and how to send personalized emails from Excel.

Updated September 2026

Why classic Word mail merge stops working

New Outlook cannot accept the messages Word’s merge hands over, so Word has nowhere to deliver them. Microsoft treats this as expected behaviour rather than a bug: there is no fix coming, and nothing on your side to repair. Microsoft’s own New and classic Outlook feature comparison (14 April 2026) lists mail merge as “Partially available” in New Outlook.

What happened to your emails depends on what is installed:

• Classic Outlook is installed too: Word handed the merge to it instead. Open classic Outlook and check the Outbox, because the messages usually queue there.
• Only New Outlook: nothing was sent. The merge completes in Word, no error appears, and no message leaves your computer.
• On a Mac: Word can still merge, but only through Outlook for Mac set as the default mail app, with no preview, and with the Excel file closed. Many people report nothing sending at all.

How to send a mail merge from Excel in New Outlook

SecureMailMerge is an add-in from Microsoft AppSource, published by Sol Inventum OÜ, the mail merge expert for Outlook 365. It adds a mail merge panel to the compose window, reads your Excel or CSV, and sends one email per row from your own mailbox. Nothing to install on the PC, nothing to set up in Word, and the add-in is identical in classic, New Outlook, Mac and web. Your spreadsheet, attachments and message content stay in Outlook and Microsoft 365, and are never sent to SecureMailMerge’s servers.

Seven steps. None of them involves Word.

1. Install SecureMailMerge from Microsoft AppSource. In New Outlook, open Apps in the left sidebar, search for SecureMailMerge, and choose Add. If your organization restricts add-ins, an administrator can deploy it for everyone from the Microsoft 365 admin center.
2. Prepare your spreadsheet. Put headers in the first row, name the email-address column “To”, and use one row per recipient. Add columns for anything you want to personalize, such as first name, company or invoice number. Spreadsheet preparation and upload covers the requirements. You can also choose Outlook contacts instead.
3. Start a new email and open the add-in. Click the SecureMailMerge icon in the compose window toolbar, or find SecureMailMerge under Apps there.
4. Load your recipients. Select “Upload Spreadsheet”. The add-in reads addresses from the “To” column. Review the loaded recipients and unselect anyone you want to skip.
5. Write your message and insert the fields. Choose a column from the dropdown to place that field in the subject or body, where it appears as {{FirstName}} and each recipient sees their own value. Set a default for any column that has empty cells.
6. Send yourself a test. Check the first recipient’s merged values, formatting, links and attachments. If you also want to inspect every generated message, use a timed draft review: messages send automatically when the delay ends, so this is not an approval step.
7. Start the mail merge. The add-in calls it a campaign on screen. It generates the messages in your mailbox and sends them from your own address, one per recipient, with copies in your Sent Items.

When it finishes, download the send report before starting another campaign. To interrupt a campaign, see pause, resume or stop a campaign.