Katalon won’t start running using the current browser session opened by Katalon

This is my first attempt to invoke a test case while choosing the already-opened browser and to reuse the running session between a browser and a webdriver instance.

I don’t know the name of this feature. Does anyone know if it is ever named? I don’t know if this is explained anywhere in the katalon’s official document. I wonder how @alyaraihanah found this.

I guess, even Katalon developers who developed v11.0.0 possibly weren’t aware of the feature, so they didn’t test it.

I don’t understand for what purpose this feature is useful. Personally I don’t need it.

This feature is very helpful if you want to continue your test without starting from the beginning, since “Run from Here” is only available on the paid plan.

Just done install katalon version 10, and the problem is solved. thankyou guys

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so basically @alyaraihanah found a loophole/workaround in the free version to get behavior similar to the paid “Run from Here” feature? :exploding_head:

Celebrate The King GIF by Manchester United

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I guess so

Happy Toddlers And Tiaras GIF

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Now they realized a loophole. I suppose that they might change this nameless feature to be an Enterprise one in future.

I wouldn’t mind 'cause I don’t need it.

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yeah, that’s likely :sweat_smile:
once a workaround gets popular, it usually gets gated or reworked

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…that is obvious :stuck_out_tongue:

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katalon would be grateful to you!!

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When explaining this to the community, highlight that “Standard WebDrivers are stateless by design.” To provide a solution, you are moving from Local Execution to Remote Debugging Protocol (RDP). This shows you understand the underlying architecture of how browsers communicate with automation tools.

Here is the fix to achieve Session Reuse:

1. The “Talk”: Why it fails

Katalon usually looks for a specific Remote Debugging Port. If you just open Chrome manually, that port is closed. Katalon can’t “see” it. To fix this, you must launch the browser in debug mode.

2. The Solution: Use “Remote” Execution

Step A: Launch your browser manually via Command Line

You must open your browser (e.g., Chrome) with a debugging port enabled so Katalon can “hijack” it.

  1. Close all Chrome instances.

  2. Open your terminal/command prompt and run:
    chrome.exe --remote-debugging-port=9222 --user-data-dir="C:\selenum\AutomationProfile"
    (This opens a browser that is “listening” for Katalon).

Step B: Configure Katalon to “Attach”

Don’t use WebUI.openBrowser(). Use the Desired Capabilities to point to that port.

  1. In Katalon, go to Project > Settings > Desired Capabilities > Web Service > Chrome (or your specific provider).

  2. Add a property:

    • Name: debuggerAddress

    • Type: String

    • Value: localhost:9222

Step C: The Script Fix

In your test case, you still need to “start” the driver, but it will now attach to the open window instead of launching a new one:

groovy

import com.kms.katalon.core.webui.keyword.WebUiBuiltInKeywords as WebUI

// Do NOT pass a URL here, it will use the existing session
WebUI.openBrowser('') 
WebUI.navigateToUrl('https://your-site.com')

Use code with caution.


3. The “Smart” Alternative: Debug from a Specific Step

If you just want to stop the test, fix code, and continue without restarting:

  • Use Right-click on a step > “Run from here”.

  • Katalon will attempt to keep the current browser alive if it was the one opened by the previous execution.

  • This can help

Thanks everyone for the detailed discussion and especially @stevio052002 for the architectural explanation around WebDriver and RDP.

I’d like to share an update specifically for Katalon Studio 11 users who are facing this issue when trying to continue execution using the existing browser session.

We were able to reproduce the behavior in KS 11, and it appears to be related to the new Execution Viewer (currently marked as Beta), not to the underlying WebDriver or Remote Debugging mechanism.

Temporary Workaround (Recommended for KS 11)

You can restore the previous behavior by disabling the new Execution Viewer:

Project → Settings → Execution
Uncheck: “Enable New Execution Viewer (Beta)”

After turning this off, you should be able to reuse the existing browser session as in earlier versions.

Clarification

This issue occurs even when the browser was originally opened by Katalon (so it is not the standard “manual Chrome without remote debugging port” scenario). The failure is triggered inside the execution handler layer, where KS 11 cannot correctly map the ExistingExecutionHandler to a DriverType, resulting in a NullPointerException.

If you specifically need session reuse across manually launched browsers, then the Remote Debugging approach described above is valid and technically correct. However, for users upgrading from KS 10.x expecting the same “Run using existing session” behavior, disabling the new Execution Viewer is currently the simplest solution.

Our engineering team is reviewing this behavior in KS 11 to determine whether it is an unintended regression or a design change in the new execution flow.

We’ll share updates once we have confirmation.

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kindly keep us posted

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useful information

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Hi everyone,

Quick update on this issue.

We have released Katalon Studio 11.0.1 today, which includes a fix for the problem where execution could not continue using the existing browser session.

If you were encountering the error related to ExistingExecutionHandler or the failure to reuse the current browser session in KS 11.0.0, please upgrade to 11.0.1 and verify the behavior again.

You can download the latest version from the Katalon website or use the in-app update if available.

Please let us know if the issue still persists after upgrading.

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Hi, I just tried it on the latest update and it works. Katalon is able to reuse the currently open browser

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Thank you for the turnaround!!

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