Unfortunately, there is no built-in prevention of duplicates while importing media into Cinegy Archive. However, it is possible to create a PowerShell script that will search the database for the existing media with the same Traffic ID and delete it if required. Such script can be developed based on, for example, the following one:
https://github.com/Cinegy/Cinegy.Powershell/blob/master/Cas/CAS-Query-Search.ps1
Such script should run independently before importing the actual media and be provided with the Traffic ID to be checked.

Another option is to use the Convert pre-processing script to automate running the script above and getting the required Traffic ID from the task itself. Such script will be able depending on the script config to execute additional logic - either delete existing, create duplicate, or cancel import task.

Convert pre-processing script can use the following:
$trafficId = $provider.Metadata['src.meta.traffic_programm_id'] - to get the current item traffic id and search for it in the database
$provider.SetTaskCancelled("Cancelled from script") - to cancel the task with the corresponding message if media already exists in the database

If you need help with scripting and organizing a customer's workflow you could contact our Cinegy Professional Services at ps@cinegy.com.