The Starts in Background option is a property of the process that indicates whether the process can run in parallel with other processes on the same machine. If this option is enabled, the process can run as a background process, meaning that it does not require user interaction or UI automation. This allows the process to run concurrently with another process that performs UI automation, such as the second process in the question. The Starts in Background option can be configured in the project settings of the process in UiPath Studio, or in the process settings in Orchestrator.