Unable to run UiPath UI automations after upgrading Mozilla Firefox to 135.0 version

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How to fix the UiPath UI Automations after upgrading the Mozilla Firefox to 135.0?

Issue Description

After upgrading Mozilla Firefox to 135.0, the UiPath UI automations fail and the targeted Ui selection cannot be performed anymore.

Indicate target on screen fails with this warning message:

"Cannot access the indicated browser window.

Note: If using Incognito Mode, please enable the UiPath extension for Incognito Mode.

If using a browser running instances with different user profiles, please install and enable the v23.10 UiPath extension or a more recent version."

kb-0EMPa00000F2SIv.png546×172 35.8 KB

UI activity will fail at runtime with this error:

"UiPath.UIAutomationNext.Exceptions.UiAutomationException: Cannot communicate with the browser, please check the UiPath extension. ---> System.Runtime.InteropServices.COMException: Exception from HRESULT: 0x80040234 at UiPath.UiSystemClass.StartBrowser(String bstrSelector, String bstrURL, String bstrArguments, UiBrowserName browserType, Int32 timeoutMs, UiBrowserFlags browserFlags)

at UiPath.UIAutomationNext.Services.UiSystemService.<>c__DisplayClass15_0.<StartBrowser>b__0()

at UiPath.UIAutomationNext.Services.DriverServiceCore.WrapCom[T](Func1 toExecute) --- End of inner exception stack trace --- at UiPath.UIAutomationNext.Extensions.ExceptionExtensions.GetFriendly(COMException comException) at UiPath.UIAutomationNext.Extensions.ExceptionExtensions.ThrowFriendly(COMException comException) at UiPath.UIAutomationNext.Services.DriverServiceCore.WrapCom[T](Func1 toExecute)

at UiPath.UIAutomationNext.Services.UiSystemService.StartBrowser(IOpenBrowserRequest request, CancellationToken token)

at UiPath.UIAutomationNext.Services.DriverBrowserService.<>c__DisplayClass15_0.<<OpenBrowserAsync>b__0>d.MoveNext()

--- End of stack trace from previous location ---

at UiPath.UIAutomationNext.Services.DriverApplicationService.StartBrowserAsync(ITargetApp target, CancellationToken token)

at UiPath.UIAutomationNext.Services.DriverApplicationService.ActivateBrowserInternalAsync(ITargetApp target, CancellationToken token)

at UiPath.UIAutomationNext.Services.DriverApplicationService.ActivateApplicationAsync(ITargetApp target, CancellationToken token)

at UiPath.UIAutomationNext.Activities.NApplicationCard.GetMainWindowByTargetApp(IActivityContextWrapper context, ITargetApp targetApp, CancellationToken cancellationToken)

at UiPath.UIAutomationNext.Activities.NApplicationCard.GetRuntimeData(IActivityContextWrapper context, CancellationToken cancellationToken)

at UiPath.UIAutomationNext.Activities.NApplicationCard.OpenOrAttach(IActivityContextWrapper context, CancellationToken cancellationToken)

at UiPath.UIAutomationNext.Activities.NApplicationCard.ExecuteAsync(NativeActivityContext context, CancellationToken cancellationToken)

at UiPath.Shared.Activities.AsyncTaskNativeImplementation.BookmarkResumptionCallback(NativeActivityContext context, Object value)

at UiPath.Shared.Activities.AsyncTaskNativeActivity.BookmarkResumptionCallback(NativeActivityContext context, Bookmark bookmark, Object value)

at UiPath.Shared.Activities.ContinuableAsyncNativeActivity.BookmarkResumptionCallback(NativeActivityContext context, Bookmark bookmark, Object value)

at System.Activities.Runtime.BookmarkWorkItem.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)"

Root Cause

The new 135.0 release of Mozilla Firefox broke the way UiPath UI automations can interact and use the old ChromeNativeMessaging.exe file.

Resolution

Approach #1 - Install a new Firefox Driver Extension and set the environment variable UIPATH_ENABLE_FIREFOX_135_WORKAROUND for each impacted robot VM

  1. Download DriverExtensions_v25.2.zip and extract it anywhere on disk (e.g. D:\DriverExtensions_v25.2)
  2. Run with Administrator rights this PowerShell command: 
    &"D:\DriverExtensions_v25.2\SetupExtensions.exe" /firefox-policy-offline /silent
  3. Set the environment variable UIPATH_ENABLE_FIREFOX_135_WORKAROUND with the value 1.
    Run with Administrator rights this PowerShell command: 
    [Environment]::SetEnvironmentVariable('UIPATH_ENABLE_FIREFOX_135_WORKAROUND', '1', 'Machine')

    This will upgrade the ChromeNativeMessaging.exe used by the Firefox extension and fix this issue.

    No changes will be required to existing automation processes.

    Approach #2 - Roll back the Firefox version to 134.0.2 and stop the browser auto-update for each impacted robot VM

    Downgrade the Firefox version to version 134.0.2 and change the settings not to update automatically.

    Disable Updates from Firefox

    1. Open Firefox and type about:config in the address bar.
    2. Search for app.update.auto and set its value to false.
    3. Search for app.update.enabled and set it to false (if present).
    4. Search for app.update.service.enabled and set it to false.
    5. Restart Firefox.

    Approach #3 - Upgrade the UiPath.UIAutomation.Activities to v23.10.16, v24.10.12 or higher

    A fix for this is released for UiPath.UIAutomation.Activities package versions:


    Important:     To automate Firefox version 135 or higher you must use UiPath.UIAutomation.Activities package v23.10.16, v24.10.12 or higher.