When you set up offline folders, you can choose to download the address book. However, address books may be very large, so you don't want to download the entire book each time you synchronize. Instead, download only the changes that occurred since the last time you synchronized.

Download address book changes only

1. While online, click Inbox.
2. On the Tools menu, point to Synchronize, and then click Offline Folder Settings.
3. Under Options, select the Download offline address book check box, and then click Settings.
4. Select the Download changes since last synchronization check box.
5. Under Information to download, click No details.