Start process as unattended robot when a file is written to a folder

You can try using an event trigger through orchestrator. Use the below links to get a better understanding

  1. https://docs.uipath.com/orchestrator/automation-cloud/latest/user-guide/event-triggers
  2. https://docs.uipath.com/orchestrator/automation-cloud/latest/user-guide/creating-an-event-trigger
  3. How we can event trigger a robot through Orchestrator?