By default, incremental changes to the OAB are downloaded on Send/Receive and the option to download incremental OAB updates since the last Send/Receive (set by default) is not displayed to users. When this setting is enabled, the option appears on the Offline Address Book dialog box. Users can clear the option, so a full OAB update is downloaded on Send/Receive. Note that a full OAB is not downloaded more than once in 24 hours, regardless of whether users set or clear this option.
|Registry Path||software\policies\microsoft\exchange\exchange provider|