Agents Sharing the Same Agent ID<!-- /*NS Branding Styles*/ --> .ns-kb-css-body-editor-container { p { font-size: 12pt; font-family: Lato; color: #000000; } span { font-size: 12pt; font-family: Lato; color: #000000; } h2 { font-size: 24pt; font-family: Lato; color: black; } h3 { font-size: 18pt; font-family: Lato; color: black; } h4 { font-size: 14pt; font-family: Lato; color: black; } a { font-size: 12pt; font-family: Lato; color: #00718F; } a:hover { font-size: 12pt; color: #024F69; } a:target { font-size: 12pt; color: #032D42; } a:visited { font-size: 12pt; color: #00718f; } ul { font-size: 12pt; font-family: Lato; } li { font-size: 12pt; font-family: Lato; } img { display: ; max-width: ; width: ; height: ; } } Symptoms: Agent does not appear on the instance.IP address is flipping on the agent record.Agent name is flipping on the agent record.The "Host" field on the Agent record is blank, but data collection appears successful.The Agent Issues table shows multiple ACC-4004 errors.When viewing the Agent form, the "ACC Error Messages" related list shows ACC-4004errors in "Active Error" state. Root Cause: This issue is caused by copying the agent cache folder (specifically the agent_now_id file) as part of a golden image used during host deployment. The agent_now_id file is located at these default paths: Windows: 'C:\ProgramData\ServiceNow\agent-client-collector\cache\agent_now_id'macOS: '/Library/Application Support/ServiceNow/agent-client-collector/agent_now_id'Linux: '/var/cache/servicenow/agent-client-collector/agent_now_id' Why This Happens: The agent_now_id file uniquely identifies an agent on the instance. When this file is duplicated across multiple hosts, all agents report using the same agent ID. As a result, only one record appears in the agent table, and all agents with the same agent ID update this shared record — causing data inconsistencies like hostname/IP flipping and missing agents. Deployment Best Practice: The agent_now_id file should not be included as part of the golden image. The file should be deleted before making the image of the VM. This way, when the new agents are deployed, the agents will generate a new agent ID instead of using the same agent ID. Resolution: Identify Impacted Hosts: The system logs duplicate agent detection as ACC-4004 errors. Check the Agent Issues table for these errors. The key column lists the agent IDs that are being detected as being shared across different agents. The key_extension column lists all affected agents using the format Agent_<hostname>. Fix Steps: Delete theagent_now_idfile on each affected host. Restart the agent service on each affected host. This will cause each agent to generate a new unique ID and register correctly. Auto resolution of this issue is available starting agent installer v5.0.0. Update Set: For agents that are on a version lower than v5.0.0, an Update Set can be applied to the Instance to support Duplicate Agent ID Auto Remediation. DISCLAIMER: This Update Set should ONLY be applied in environments where there are only Windows agents. If deployed on an Instance with Linux agents, there is a chance that the Linux agents will not come back online after the auto-remediation is executed on the agents. KB2200106: Duplicate Agent ID Detection and Remediation Update Set Detection False Positives: The duplicate agent detection is based on hostnames.If a hostname changes, it may trigger an ACC-4004error.However, if the issue is not seen again within 24 hours, it is auto-resolved by the system. Know Issues with Duplicate Agent ID detection/resolution: PRB1902306 : Duplicate Agent ID Error will not resolve if agents are down when job runs