If your Outlook address book is out of sync with the Global Address Book, you may notice missing or incorrect entries. You can manually synchronize your address book with the Global Address Book.
1. Open Microsoft Outlook and click on "File" in the top left corner.
2. Click on "Account Settings" and then select "Download Address Book..." from the dropdown menu.
2. Uncheck ‘Download changes since last Send/Receive', then click ‘OK’.
3. The update can take a few minutes to complete.