Please visit the document on How to turn on or off Cached Exchange Mode for (Outlook 2010, and Outlook 20).
Outlook 2011 does not use Exchange Cached mode and directly connects to the Global Address Book (GAL) via LDAP connection.
This document seeks to address and clarify the small misunderstanding surrounding the GAL (Global Address List) and the OAB (Offline Address Book).
If this is happening, then you may notice missing, non-existent and/or incorrect entries.
GAL Objects are directly viewable in the Exchange Management Console/Shell and OWA and Microsoft Outlook BUT ONLY IN ONLINE MODE – The GAL will only present objects that have AD Attributes beginning with ms EXCH* (and some others) populated that it uses to filter on.
If these attributes are present, then the AD Objects that are Mail-Enabled or Mailbox-Enabled will appear in the GAL – and ultimately the Offline Address Book.
However sometimes in large complex organisations we have a situation where a new joiner joins and their colleagues want to email them immediately, but they don’t appear in Outlook for them so they call the Helpdesk “Why isn’t Joe Bloggs in the GAL??
” Well, the truth of the matter is that our new joiner Joe is in fact , an update to the Address Book won’t become available to the user until about 48 hours after the change.