Update Outlook Address Book
This solution runs through the steps to retrieve the latest Address Book from Exchange or Exchange Online.
NOTE: Each day Outlook starts it will retrieves the latest Address Book.
1. While using Outlook, click on the "Send / Receive" ribbon menu
2. Click "Send / Receive Groups"
3. Click "Download Address Book"
4. Click "OK"
5. The "Outlook Send / Receive Progress" window will appear and disappear when complete
If there is a distribution list that should be updated, now is the time to check it by expanding the list in a new message window.