To enable Cached Exchange Mode, follow the steps below for your version of Outlook: Please double-check that the Cached mode is enabled and the offline data file was created to access the mailbox. Note: It is impossible to use the feature Work Offline if the Outlook is in Online mode. This may help improve the performance of Outlook on slow Internet connections. Outlook and the Exchange Server synchronize the local and server data periodically. Outlook accesses this cached copy for most operations speeding response times. While Online Mode maintains a direct connection to an Exchange server, Cached Exchange Mode creates a local copy of the mailbox data stored on the Exchange server in an offline data file (.ost file). There are two ways to connect Outlook to an Exchange account: Online Mode and Cached Exchange Mode.
Important: this article applies to Outlook for Windows only.
