The Clients tab of the Symantec Endpoint Protection Manager (SEPM) contains multiple client entries with the user name listed as "None" when deploying a User Mode Symantec Endpoint Protection (SEP) client package to computers without a logged in user.
A SEP client is assigned a unique Client ID based on the username of the logged in user, and the Windows domain/workgroup the computer belongs to. Each time one of these changes, the client will be forced to re-register with the manager, which generates a new Client ID.
When you deploy a client package in user mode to a computer with no user logged in, the manager creates a Client ID with a blank username, and the computer's Windows domain/workgroup. If the computer restarts automatically after the installation, the client may register in with a blank username and domain, creating a new Client ID in the SEPM database. Each subsequent user that logs into the computer will generate a new Client ID entry in the database.
These entries can be safely deleted from the console. If you choose not to remove these entries, they will be deleted automatically based on your domain configuration for inactive client deletion.