How to Fix Mail Merge Not Working in Office 365: 4 Ways

Meeting mail merge not working in Office 365? Read this article to know how to fix it with 4 easy methods and an easy tool to backup Office 365 email for data security.


By Jonna Updated on October 23, 2023

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Overview of Mail Merge

Mail merge is a powerful feature in Outlook, automating the process of creating personalized mass emails by integrating data from a spreadsheet or database file. This functionality allows users to fetch details of multiple recipients from a source file and insert them into an email message template, facilitating efficient and customized communication.

While mail merge enables personalized emails to be sent to numerous recipients, it can be a challenging process in Outlook. This is because users often find themselves switching between three different applications (Microsoft Word, Excel, and Outlook) to send merged emails. Thus, there are instances where users encounter mail merge not working in Office 365.

Outlook Mail Merge

For users seeking guidance on performing a mail merge in Outlook, follow these step-by-step instructions:

Step 1. Prepare your email content using Microsoft Word.

Step 2. Set up your mail merge data in Microsoft Excel.

Step 3. Link the mailing list with the email message.

Step 4. Preview and complete the mail merge process.

Step 5. Send the mail merge messages.

Why is My Mail Merge not Working?

Troubleshooting Outlook mail merge issues can be a bit tricky since there can be various reasons why it might not be working as expected. Here are some common factors that may cause mail merge is not working:

Cause 1. Data Source Issues

Your source file may not be properly set up or do not contain the correct information.

Cause 2. Incorrect Merge Fields

You have inserted the wrong merge fields in your mail merge document.

Cause 3. Formatting Issues

The data in the data source and the merge field in the document have inconsistent formats.

Cause 4. Protected Document

Your mail merge document is protected, preventing the merge from working correctly.

Cause 5. Field Codes Displayed

If you see field codes (e.g., {MERGEFIELD}) instead of the actual data, try toggling the field codes on and off.

Cause 6. Compatibility

You are using incompatible software versions for your mail merge process (e.g., Microsoft Word, Excel, or Outlook versions).

How to Fix Mail Merge not Working in Office 365 in 4 Methods

If you're experiencing Office 365 mail merge not working, here are some steps you can follow to try and fix the problem.

Way 1. Edit Existing Address List

If there are errors with your existing address list, you can make changes to your data source or address list to resolve mail merge not working in Word/Excel.

Step 1. In Microsoft Word, navigate to Mailings > Select Recipients > choose Use an Existing List. Then, select Next: Create or connect to a recipient list.

Use An Existing List

By default, Microsoft Publisher stores data sources in the My Data Sources folder. If your data source is not located there, you may need to browse to find and select it.

Step 2. In the Select Data Source dialog box, click on the desired data source you want to use, and then click Open.

Step 3. Locate the name of the data source you selected and click Edit to make the necessary changes to your data source or address list.

Mail Merge Recipients

Step 4. Edit or delete existing addresses in the Edit Data Source box, or add a new entry. Click OK and then Yes to save the address list changes.

Way 2. Select Dynamic Data Exchange Option

During mail merge in Outlook 365, Word utilizes OLE DB Database Files to fetch information. However, to address potential issues with data source compatibility, you can utilize the Confirm file format conversion on open option, which provides various Open data source options. Selecting MS Excel Worksheets via DDE (*xls) allows Word to restore the cell formats of Excel files and may help resolve any mail merge failures.

Step 1. In Microsoft Word, go to File > Options > Advanced > General > tick the Confirm file format conversion on open option.

Word Option Advanced

Step 2. Then navigate to Mailings > Select Recipients > select Use an Existing List.

Step 3. Choose the desired Excel file containing the recipient data. Then, the Confirm Data Source dialog box will open.

Step 4. Tick Show all checkbox. Then, select MS Excel Worksheets via DDE (*xls) to preserve the Excel file format and resolve any mail merge not working in Office 365 issues.

Confirm Data Source

Way 3. Insert Space in Merge Fields

The most common issue when inserting merge fields in a document is managing the correct spacing between the fields, especially with merge fields that may not always be present, such as middle initials. Adding spaces directly on the page between the merge fields can lead to unwanted extra spaces if some addresses do not use all the fields.

For example, to ensure the correct appearance of recipients' names, regardless of the presence of a middle initial in your address list, follow these steps:

  1. If a recipient has a middle initial, insert a space before and after the initial in the Middle Initial entry by pressing the space bar.
  2. For recipients without a middle initial, add a space in the Middle Initial entry.

Edit Data Source

Way 4. Repair Office application

Frequently, a malfunctioning Microsoft issue, such as mail merge not working in Outlook, can be attributed to an outdated or corrupted application caused by an operating system upgrade. To address this problem, follow these steps to repair the application:

Step 1. Click on Settings and choose Apps.

Step 2. On the left menu, select App and features, then locate the Microsoft Word, Microsoft Office, or Microsoft 365 application.

Step 3. Click the Modify button, followed by selecting Quick Repair > Repair to initiate the automatic repair process for Microsoft Office.

Modify Microsoft App

Bonus Tip: Quick Way to Backup Office 365 Mailbox

Maintaining regular backups of your Office 365 emails is of utmost importance, regardless of whether you're conducting a mail merge or not. This practice ensures enhanced security for your crucial email data. For this task, AOMEI Backupper Professional stands as an excellent choice.

Here's why AOMEI Backupper Professional is a reliable option:

☎ Its "Email Backup" feature enables you to back up all your emails, contacts, notes, calendars, and tasks in Outlook, even without using the Outlook desktop app.
☎ Its Schedule Backup feature allows you to automate the email data backup process, ensuring convenience and consistency.
☎ The software allows to backup Outlook emails to external hard drives, local disks, USB flash drives, NAS devices, and more, offering flexible storage options for your Outlook emails.
☎ In addition to Office 365, it also provides to backup Yahoo Mail, Gmail, Zoho Mail, Hotmail, iCloud Mail, HushMail, and dozens of popular email services.

To back up all your Office 365 email using this software, download and install it on your computer. Then, follow these steps:

Download Free Trial Win 11/10/8.1/8/7/XP
Secure Download

Step 1. Launch AOMEI Backupper Professional. Click Backup and then Email Backup.

Email Backup

Step 2. Click Add Email data and select the specific Office 365 emails you want to backup. Then click OK.

Add Email Data

Step 3. If you want to store the backup image file on hard drive, you can choose Select a local path.

Select Destination Path

Step 4. Click Schedule Backup to set up Daily, Weekly Monthly, Event trigger, or USB plug in auto backup. Ensure the option Wake the computer to run scheduled tasks is checked.

Schedule Settings General

Step 5. Tap on Start Backup to backup Office 365 emails automatically.

Start Backup

By default, the software uses Incremental Backup, which backs up only changed files when you enable scheduled backups. You can switch to Differential Backup if needed.
To prevent the backup disk full, this software allows you to delete old backup images on a regular basis. Click Backup Scheme to enable it.


This article sheds light on the possible causes of mail merge not working in Office 365 and provides solutions to resolve it.

Additionally, it emphasizes the importance of regularly backing up your Office 365 emails for added safety. AOMEI Backupper offers a comprehensive solution, not only enabling automated backups for Office 365 emails but also offering to backup Windows systems, hard disks, partitions, and private files. You can store these backups on various locations, including hard disks, cloud disks, NAS, and more.

Jonna · Editor
Jonna joined AOMEI in 2021 and has become a professional in the areas of computer backup and restoration, disk cloning, file synchronization, etc. She maintains a keen eye for the latest technology trends, ensuring that the information provided is always in step with industry developments.