How to Switch from Mixed Mode to Native Mode
Topic Last Modified: 2005-05-04
By default, a new Exchange 2003 organization runs in mixed mode until it is promoted to native mode. This procedure outlines how to switch your Exchange Server from mixed mode to native mode.
You can only promote an Exchange organization to native mode if there are no servers running Exchange 5.5 (or earlier), and if no instances of Site Replication Service (SRS) are running. Also, make sure that you have correctly upgraded all servers and any connectors before you switch to native mode. After you switch an organization to native mode, it can never return to mixed mode. This means you cannot add an Exchange 5.5 server to a native mode topology.
In Exchange System Manager, right-click your Exchange organization, and then click Properties.
On the General tab (see the following figure), click Change Mode.