"The specified display name is already in use by another agent" when Adding a machine to Protection (4033364)

A machine was removed from protection and the recovery points were kept.  Adding the same server back to protection presents the error, "The specified display name is already in use by another agent."  Your objective is to put the recovery points only inline with the re-protected server.

An Agent with the same display name has been found in the Core UI.

The goal is to get the AgentID back to the newly rebuilt or reinstalled Agent machine.

1. On the Core UI, navigate to the Recovery points Only machine name.
2. Look at the address bar for a unique identifier, similar to what is highlighted in the below image.

• Access the server that needs to be added back to protection
• Stop the Agent service in services.msc
• Open the regedit and navigate to:  HKEY_LOCAL_MACHINE\SOFTWARE\AppRecovery\Agent\AgentId
• Change the AgentId key to the key from the URL
• Start the Agent service
• Add the Agent to protection on the core.