Error: 'an instance of the service is already running' appears when an DMA/SC agent is launch to a machine.
The process DCTAgentService continues to run on the DMA console machine after the agent task has completed and cannot be killed.
Ultimately, this error is the result of an agent that was launched to a machine and not properly stopped. One of the potential causes of this error is the lack of bandwidth necessary for successful communication using RPC.
Since the agent is installed using RPC, NetIQ recommends 128kps connection speed between the DMA console and agent machines.
One of the following can be done to stop the agent to continue any agent task:
- Use Service Control Manager or the the services node in Computer Management on the agent machine to stop the Domain Migration Administrator Agent service.
- On the agent machine:
- Open Task Manager.
- Go to the Processes tab.
- Select the process called ADMTAgnt.exe.
- Click End Process.
- Click Yes to confirm.
- Repeat the process for the DCTAgentService process.
C:\> sc.exe \\ computername delete OnePointDomainAdminService