WinAutomation may execute a Process in a Non-Interactive Mode, only if it does not contain any interactive Actions. Check the list of Interactive/Non-Interactive Actions.
Interactive Actions require an active screen. So, the machine should be unlocked and the user logged in.
The running mode can be defined from the Run Policy tab in the Properties window of a Process.
If privacy is a concern while using executing interactive processes, this can be overcome by applying the Secure Screen option which can be enabled in the General tab. The secure screen blocks anybody from viewing what is happening on the screen and actions to disable keyboard and mouse inputs can be incorporated ("Block Input" Action). It's also possible to add the "Lock Workstation" Action at the end of the process, to ensure the screen is locked upon successful completion or even through exception handling in the event an action fails during execution.