After installation of a new DLP agent, it does not show in the console. However, a review of the aggregate logs that were produced with the finest level log output confirms communication with the Endpoint Server.
Agents do not send an "Up" status to the console. Troubleshooting tasks run but they may not report as successful in the console.
This problem is due to a process deadlock with the Monitor Controller on the Enforce Server.
Restart the Monitor Controller on the Enforce Server.
Restarting the Monitor Controller can be done in the Windows service console or the Enforce console.
This issue has been fixed in 14.6 MP3 and later.