If you have a need to mail merge from a shared mailbox, ensure that you have the following as well:

• Permissions to the Shared Mailbox in Question (full access)
• Outlook 2013 (PC) or 2016 (Mac), or OWA

Procedure:

1. First, go to Adding a Second Profile in Outlook for O365 - Powered by Kayako Help Desk Software (osu.edu) to set your shared mailbox up as a second profile, if you haven’t already done this
2. Open Outlook to the appropriate profile
3. Put Outlook in Offline Mode
   1. Go to the Send/Receive tab and select the Work Offline button
      
   2. If you are using Office 2016 for the Mac, go to the Tools tab and toggle the Online/Offline button
      
4. Open the document you want to send via MailMerge
5. Go to the Mailings tab
   
6. Click Select Recipients and go to “Use Existing List”
7.  Use the dialog box to navigate to and open the data spreadsheet
8. Select the appropriate table in the text dialog box
   1. If necessary, select Edit Recipient List and de-select all unwanted data
9. Select Finish and Merge
10. Go to Send E-Mail Messages
11. In the “Merge to E-mail” dialog box that comes up, verify that the “To:” field and the “Subject line” field show the correct fields. Then verify that the mail format is HTML. Click OK.
12. The emails will then propagate in your Outbox in Outlook
    1. If you want to, you can open them up and manually edit any information in. For example, in the “CC” field you could add additional reciepents on an adhoc basis.
13. When you are sure that the the emails are correct, turn Outlook back into Online mode and the messages will be sent