Outlook cached mode not updating
You can disable caching of all shared folders for profiles that have Cached Exchange Mode enabled.
To do this, configure the Download shared non-mail folders option in the Office Customization Tool (OCT) when you customize your Cached Exchange Mode deployment.
So, when you use Cached Exchange Mode, Outlook must be connected and open at the assigned delivery time for the delayed delivery message to be sent.
For more information about how to configure this and other settings, see Using Group Policy and the Office Customization Tool (OCT).
Most users find that Cached Exchange Mode performs faster than online mode.
Cached Exchange Mode gives users a seamless online and offline Outlook experience by caching the user's mailbox and the Offline Address Book (OAB) locally.
With Cached Exchange Mode, which is the default setting for users, Outlook no longer depends on continuous network connectivity for access to user information.
When a user is connected, Outlook continuously updates users' mailboxes so that the mailboxes are kept up to date.