
Note The default setting on the Exchange computer is to generate an offline address book differential file every morning at 04:00. For a change that is made in Active Directory to reach the client computer, the following events must occur:
-
The change must be picked up by the Exchange computer that generates the offline address book files. This can take several hours. At worst, it can take 24 hours. This variable will be referred to as “x.”
-
The Outlook clients must download the offline address book updates every 24 hours. This update can take several hours. At worst, it can take 24 hours. This variable will be referred to as “y.”
The update reaches the client machines x+y hours later. It would be rare for a client to ever experience a 48-hour delay or more unless there were some Active Directory or public folder replication issues.
More Information : http://support.microsoft.com/kb/841273