Store.IsCachedExchange Property (Outlook)
Returns a Boolean that indicates if the Store is a cached Exchange store. Read-only.
IsCachedExchange returns True when Store.ExchangeStoreType is a primary Exchange mailbox (Store.ExchangeStoreType is olExchangePrimaryMailbox) and the mailbox is configured to use cached Exchange mode. It returns False otherwise. In particular, it returns False for an Exchange Public Folder store that is configured to cache Public Folder favorites.