When the Outlook Address Book service is not included in an Outlook profile, or the Contacts folder is not selected to be included in the Outlook Address Book, Contacts can not be added to a mail message by clicking on the To: button in a new mail message.

To add the Outlook Address Book service to the Outlook profile:

- In Outlook select Tools | E-mail Accounts
- Click the "Add a new directory or address book" radio button and click Next
- Select the "Additional Address Books" radio button and click Next
- Select "Outlook Address Book" and click Next
- Click OK to the "The E-mail Account you have just added will not start until you choose Exit from the File menu, and then restart Microsoft Office Outlook" message
- Select File | Exit from the menu
- Open Outlook

To select the Contacts folder to be included in the Outlook Address Book:

- If the Contacts folder cannot be seen, select Go | Folder List from the menu
- Right click on the Contacts folder and select Properties from the context menu
- Select the "Outlook Address Book" tab
- Check the "Show this folder as an e-mail Address Book" checkbox and click OK

In a new mail message:

- Click the To: button
- Click the "Show Names from the:" dropdown list
- Select Contacts under Outlook Address Book