I have checked the log, it still prints the same message.
Starting up SwarmAgent …
… registering SwarmAgent with remoting service
… registering SwarmAgent network channels
[ERROR] Channel already registered, suggesting another SwarmAgent or client is running.
[ERROR] If you feel this is in error, check your running process list for additional copies of
[ERROR] SwarmAgent or UnrealLightmass (or other client) and consider killing them.
[ERROR] Sleeping for a few seconds and trying again…