19.2 Robot Session (Picture in Picture): Child Session vs. Virtual Desktop

19.2 Robot Session (Picture in Picture): Child Session vs. Virtual Desktop

Core Concept: A Robot session, previously called Picture in Picture (PiP), runs an attended automation isolated from the user's own work, so both can use the machine at once. There are two technologies: Child Session and Virtual Desktop.

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The Two Technologies

UiPath's guidance: Child Session suits complex automations that need hardware events and image-based automation, while Virtual Desktop is recommended when both work, because it is faster and lighter.

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Enabling Child Session PiP

Child Session PiP must be enabled on the machine:

• On an existing installation, run UiRobot.exe PiP --Enable (or --Disable) with administrator rights; the setting affects all users of the machine.
• During a command-line installation, pass ENABLE_PIP=1 to the installer.

Things to remember about Child Session:

• You cannot restart or shut down the machine while the Robot session is active.
• The clipboard is shared between the Robot session and the main session.
• PIN and smart-card sign-in work only the first time a session is spawned; after that, the session is authenticated with username and password until the machine restarts.

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Configuring Processes for a Robot Session

In Studio's Project Settings, the PiP Options record whether the project was tested in a Robot session and whether it starts there by default:

PiP Type chooses New Session (child session) or New Desktop (virtual desktop).

In Studio, the Picture in Picture option on the Debug tab runs or debugs the process in a separate session or virtual desktop so you can test it before setting these options.

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Choosing Where Invoked Workflows Run

Invoke Workflow File can choose a target session for the invoked workflow:

A common design runs the background-safe parts in the Robot session and switches to Main for steps that must interact with the user's session, such as a message to the user or an application that cannot run twice.

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Design Tips

• Choose input methods that work in both technologies. Prefer Simulate, or Windows Messages where the application supports it. Avoid hardware events if the process must run in a Virtual Desktop.
• Avoid image-based steps if you want Virtual Desktop.
• Watch shared resources. Both sessions share the clipboard and some applications allow only one instance per user; design around this, for example by not using copy and paste to move data.
• Test with PiP on in Studio before marking the project as tested.

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Testing Checklist Before Marking a Project as Tested for PiP

1. Run the process in Studio with the Picture in Picture option on the Debug tab, using the PiP Type you intend to publish.
2. Confirm every UI step works with the chosen input methods.
3. Check steps that use the clipboard or single-instance applications while the user is working in the main session.
4. Only then set PiP Options to one of the "Tested for PiP usage" values and publish.

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Worked Example

An HR onboarding automation fills forms in a web HR system and a desktop payroll client.

• The web steps use Simulate input and work in both technologies.
• One payroll screen only responds to hardware events, so the team chooses Child Session (PiP Type New Session), enables PiP on the machines with UiRobot.exe PiP --Enable, and marks the project Tested for PiP usage; Starting in PiP.
• A final confirmation dialog is invoked with target session Main so the HR specialist sees it in their own session.

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Common Traps

• Virtual Desktop does not support hardware events or image-based automation.
• Child Session is not available on Home editions of Windows 8 and 10 and needs PiP enabled with administrator rights.
• "Not tested for PiP usage" does not block PiP; it asks the user to confirm.