Add Shared Mailbox for Mail Merge
Click on "Start" button
Select "Control Panel" item
Click on "Mail (32-bit)" link. If you do not see it, view by: Small icons
Click on "Show Profiles..." button
Choose "Prompt for a profile to be used" option
Click on "Add..." button
Click on "E-mail Address:" edit it from your email address to the shared mailbox email address. (Example: Helpdesk@ric.edu) Leave the password text boxes blank
Click on "Next >" button
Click on "User name" edit it to your full email address with numbers if you have them. (Example: jdoe_2222@ric.edu)
Check "Remember my credentials"
Click on "OK" button
Check "Change account settings"
Click on "Next >" button
Uncheck "Use Cached Exchange Mode"
Click on "Finish" button
Click on "Apply" button
Click on "OK" button
Click on "Outlook" button, it will now prompt you to select a profile. Select the shared mailbox profile to use for the mail merge.
Select "Shared Mailbox" item
Click on "OK" button
Your shared mailbox is now its own profile which is the only way to get the mail merge to work and send as the shared mailbox.