Unattended InPrivate/Incognito Browser Automation Fails with "Cannot Communicate with the Browser" Error for Cross-Platform Projects Created in Studio Web

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Why does an unattended Cross-Platform project published from Studio Web fail with Cannot communicate with the browser, please check the UiPath extension (HRESULT: 0x80040234) when the Use Application/Browser activity has IncognitoWindow = True?

Issue Description

When a Cross-Platform project is created in Studio Web and published to Orchestrator with a Use Application/Browser activity configured with IncognitoWindow = True, the unattended job fails as soon as the browser attempts to launch. The same automation runs successfully in attended mode, or when IncognitoWindow is set to False.

Environment where this occurs:

  • Project type: Cross-Platform (Portable)
  • Authored in: Studio Web
  • Execution mode: Unattended (non-serverless robot)
  • Activity: Use Application/Browser with IncognitoWindow = True

Error Message

Cannot communicate with the browser, please check the UiPath extension.

UiPath.UIAutomationNext.Exceptions.UiAutomationException: Cannot communicate with the browser,


please check the UiPath extension.


—> System.Runtime.InteropServices.COMException: Exception from HRESULT: 0x80040234


at UiPath.Driver.Portable.ExceptionGenerator.HandleResult(ReturnCode retCode, String extraData)


at UiPath.Driver.Portable.Interop.UiSystemPortable.OpenBrowserAsync(UiOpenBrowserRequest request)


at UiPath.UiFactory.OpenBrowser(UiOpenBrowserRequest request, IUIAutomationService uiAutomationService)


…


at UiPath.UIAutomationNext.Activities.NApplicationCard.ExecuteAsync(…)


HRESULT: 0x80040234 = UIAF_E_BROWSERNOEXTENSION, meaning the driver cannot establish communication with the browser extension at launch time.

Root Cause

Two conditions must both be true for unattended InPrivate/Incognito browser automation to succeed. If either condition is not met, the job will fail with the error above:

  1. requiresUserInteraction is set incorrectly. Studio Web does not set requiresUserInteraction = true when a new Cross-Platform project is created. Both project.json and operate.json are written with "requiresUserInteraction": false, which instructs the Robot to run in a non-interactive background session (Session 0) during unattended execution. In Session 0, the UiPath browser extension cannot initialize.
  2. UiPath Browser Extension is not permitted to run in Incognito/InPrivate mode. By default, browser extensions are blocked from running in Incognito (Chrome) or InPrivate (Edge) windows. If the UiPath extension does not have explicit permission to run in these modes, the extension will not load when the browser opens in InPrivate/Incognito, and the robot cannot communicate with it.

Comparison of published packages (condition 1):

project.json → runtimeOptions

  • Failing (published from Studio Web): "requiresUserInteraction": false
  • Working (fixed via Studio Desktop): "requiresUserInteraction": true

operate.json → runtimeOptions

  • Failing (published from Studio Web): "requiresUserInteraction": false
  • Working (fixed via Studio Desktop): "requiresUserInteraction": true

Resolution

Both of the following steps must be completed before the automation can run successfully unattended in InPrivate/Incognito mode.

Step 1: Enable the UiPath Browser Extension in Incognito/InPrivate mode

Google Chrome:

  1. Open Chrome and navigate to chrome://extensions
  2. Locate the UiPath Browser Automation extension
  3. Click Details
  4. Enable Allow in Incognito

1660×1297 119 KB

Microsoft Edge:

  1. Open Edge and navigate to edge://extensions
  2. Locate the UiPath Browser Automation extension
  3. Click Details
  4. Enable Allow in InPrivate

1490×1062 77.6 KB

This setting must be configured on the robot machine where unattended jobs execute.

Step 2: Correct requiresUserInteraction in Studio Web

The Starts in Background setting is now accessible directly in Studio Web, so Studio Desktop is no longer required.

  1. In the Explorer panel, right-click the UIA project
  2. Select Properties from the context menu
  3. In the right-side panel, uncheck Starts in Background (unchecking this sets requiresUserInteraction = true)
  4. Republish the project from Studio Web to Orchestrator

2457×638 66.9 KB

After both steps are complete, the unattended job runs in an interactive desktop session where the browser extension is active and permitted to operate in Incognito/InPrivate mode.