Accessing public folders that were not made available offline.Setting, changing, or canceling an Out of Office message.Working with Shared Folders that were not made available offline.These operations won't function when Outlook is not connected and can take longer to complete on high-latency connections. Large mailboxes on computers that don't have sufficient hard disk space for a local copy of the mailbox.Įven when it is configured in Cached Exchange Mode, Outlook 2016 must contact the server directly to do certain operations.

In addition, we recommend that you consider using Encrypting File System (EFS) or BitLocker as a robust solution. Heavily regulated compliance or secure environments where it is a risk to store data locally.Kiosk scenarios, where a particular computer has many users who access different Outlook accounts-and the delay to download email messages to a local cache is unacceptable.Online mode is useful in the following situations: Users who have high-latency connections (greater than 500 ms) to Exchange Server.Users who frequently work offline or without connectivity.Users who frequently move in and out of connectivity.Mailbox data is only cached in memory and never written to disk.Ĭached Exchange Mode is the preferred configuration in Outlook 2016 and is useful in the following situations: Online Mode works by using information directly from the server, and, as the name implies, it requires a connection. We recommend always using Cached Exchange Mode with an Office 365 account.

Microsoft outlook account settings