In Microsoft Outlook 2016, downloading the latest address book is essential for ensuring your contact information, such as the Global Address List (GAL), is accurate and up-to-date. This is particularly important for users in corporate environments who rely on an Exchange account for synced directory details.
You can force Outlook 2016 to fetch the most recent version of the address book using two main methods. This is the most direct way to trigger a manual download. Outlook: How to Update an Offline Address Book how to download latest address book in outlook 2016