During the initial SBS integrated setup, Exchange is installed and activated for you through an automated task. If Exchange ever needs to be repaired using the steps from the SBS 2008 technet repair guide, a reactivation of the product may be required. Upon launching Exchange 2007 Management Console, you’ll be presented with following warning:
“The following servers in your organization are currently unlicensed. If you’ve a product key, select Enter Product Key action on the server work center action pane. If you don’t have a product key, see here for information about how to license your Exchange 2007 servers.” A hotfix has recently been released that’ll activate the Exchange 2007 installation running on SBS 2008.