The OAB is being downloaded once every 24 hours if the OAB contains new data.
Impact of Cached Exchange Mode on Outlook functionalities Besides the earlier called scenarios there are some additional functionalities which are influenced when using Outlook in Cached Exchange Mode.
One of these things is the Outlook version that is in use.
It will depend on the organization but in most cases you will see that it Cached Exchange Mode will be enabled both for desktops and laptops.
This can happen if one of the following tasks is being performed: Cached Exchange Mode i.c.w.
Note that the following blog only works if you are connected to an Exchange server.Initially a complete download is being performed of the address book.After that only incremental updates are downloaded from the address book.In Cached Exchange Mode you will need leave Outlook running to index the content of the OST.When you quit Outlook Windows Desktop Search won’t index the OST. Windows Desktop Search is that the requests will be processed locally instead of sending them to the Exchange Server.If you choose to work in Online Mode make sure you are implementing Windows Desktop Search 4.0.Windows Desktop Search 4.0 is the only search engine at this moment which doesn’t create any additional read requests.When the autodiscover functionality of Exchange is being used you will see that the Cached Exchange Mode will be enabled by default. When using Outlook 2010 by default both the user mailbox and additional mailboxes are added to the cache. It is possible to add Public Folder favorites to the cache but in this case you will need to enable the option manually or via a GPO.As mentioned earlier Outlook will use an Offline Address Book (OAB).Here ends the blog about Outlook and Cached Exchange Mode.As you have seen there are a lot of things you should consider before enabling it.