Error #101: Kantu is not connected to a browser tab

Tried this:

  "Command": "store",
  "Target": "true",
  "Value": "!errorignore"
  "Command": "label",
  "Target": "test",
  "Value": ""
  "Command": "selectWindow",
  "Target": "TAB=OPEN",
  "Value": "web page url"
  "Command": "store",
  "Target": "${!LastCommandOK}",
  "Value": "continue"
  "Command": "echo",
  "Target": "${continue}",
  "Value": ""
  "Command": "gotoIf_v2",
  "Target": "(${continue} == \"false\")",
  "Value": "test"

I started macro from blank firefox page so this error was expected. I switched to “normal” page (tab) during macro execution. And I was expecting that kantu will connect to a browser tab. Which did not happen :frowning: It seems kantu does not even try to “catch” the new context.
Can something be done? And is there some good alternative (if not)? Except for iMacros which is no way as well now.

  "Command": "click",
  "Target": "xpath=/html/body/table[2]/tbody/tr[2]/td[2]/table[3]/tbody/tr/td[1]/a/img",
  "Value": ""
  "Command": "pause",
  "Target": "1000",
  "Value": ""
  "Command": "waitForPageToLoad",
  "Target": "60000",
  "Value": ""

I am getting 101 in this case also. Kantu is not capable to connect to browser tab for waitForPageToLoad…
If I leave pause command it is problematic as well. I cannot remember if it gives same or other error though.
I should add that this is not happening always. Command waitForPageToLoad might be executed correctly.
I really miss good old iMacros (with javascript scripting interface) where such problems were very rare.


I have used imacros on firefox 56 for 10 years and as established it is better than ui vision, Imacros never crashes and works without problems all day long but it has limits in the commands.

Ui vision is a good program but it has defects that have never been resolved which create a lot of discomfort for those who automate because when you automate you need the software to work perfectly. The problem of multiple tabs that open with execution of the “selectWindow” command I solved it using firefox ESR 60 and ui vision 5.1.9 it never happened with that version of firefox while it often happened to me with other versions of firefox and with others ui vision versions.

About the problem “Error # 101: Kantu is not connected to a browser tab” is an error also present in Katalon Recorder and in selenium therefore I believe that it is the basic structure of ui vision to have it and I believe that it can never be solved.

To reduce the possibility that this error occurs, I use of batch files that periodically close and reopen firefox, when the error “Error # 101: Kantu is not connected to a browser tab” occurs, you must necessarily close the browser and reopen it otherwise from at that moment no macros will work because ui vision has lost control of the tabs for this I plan periodic shutdowns of firefox to prevent this problem.

An alternative solution at “Error # 101: Kantu is not connected to a browser tab” is in the ui vision windows “Table View” select a line with a command and click “Info for this command” it open a new tab from ui vision windows and restores control of the tabs.

I love ui vision but is very hard automate with this random bug.

In my opinion after 2 years with this error i think never will be fixed.

The error #101 is somewhat of a “catch all” error for several different communication problems between extension and browser. Many of these issues have been solved by now. Maybe some other problem still show up for you, and we would love to fix it, too. But we need a test case for it:

@jathri @newuserkantu We need a test case that we can run, than we can recreate and fix this error. You (or anyone else with this issue!) can also email me at team AT and mention this forum post. Then we can give you remote access to one of our test systems (Windows, Mac or Ubuntu) and you can log in and try to recreate the error there.

Can you add option to enable debug (or other very thorough) level of logging? So we can export a proper log and send it to you to isolate the issue(s)?

I writed an email now from g******

***** to avoid spammers in the forum

Hi all and @TechSupport!

I got this error message and various others.
I tried lot of solutions but did not helped.
And I try this: pause 1-3sec before and after the command what cause error , change the generated target to shorter one. //[@id=“pelda”]/div[2]/div/a[2]/h34 to this xpath=(//[text()=‘adatok’]).
This solved the errors for me. Tested 1h and 5 windows.

Hi All,

I think the error "Error # 101: Kantu is not connected to a browser tab” happens after a popup window is closed based on my experience (not sure if there are other cases though). Try downloading Chrome extension “Open link in same tab, pop-up as tab [Free]” (link:

The extension will block popup window and open a new tab instead. I think this workaround will solve majority of "Error # 101: Kantu is not connected to a browser tab”

This is a random bug, there is not a macro code to reproduce this error because is random.

I get this error randomly after automation has been running for some time (I only have 1 window open, dedicated to the automation):

Could not establish connection. Receiving end does not exist.

Is there no way for Kantu to reconnect automatically?

There really good solution in this case is close browser, close kantu and reopen it and run again macro.

If you continue to work with this error more command give errors.

I via batch file close automatically browser every 10 minutes to prevent this problem and restart macro.

Sometimes I see this error after 30 mins, sometimes after only 7 minutes. Do you experience the same?

I start macro for a few minutes usually 5 minutes max, after I close the browser and restart the browser again with ui vision to prevent this error.

In my opinion this error is random and can not be solved because other automation software based on selenium IDE also have the same error.

Create macros that periodically close and reopen browser otherwise this error can appear at any time and there is no solution to solve it.

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I’m getting less of this error lately, for some reason.
But is there any way for Kantu to re-connect to the browser window, given the fact it’s the only window opened?

The only working solution is close browser and ui vision and restart macro.

I close my macro every 5 minutes and restart it via batch file.

Solved this by adding a wait for page to load on the 1st line of macro. This allowed time for the browser to open a tab before Kantu throws instructions at it. Hope it works for others too.

  "Command": "waitForPageToLoad",
  "Target": "20",
  "Value": ""

This do not solve this problem, You will have again this error.

“UI.Vision RPA is not connected to a browser tab” is random and can not be solved.

Katalon recorder have the same error, is a native error of selenium (base of ui vision RPA) and nothing can solve this.

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Best solution is close crome and reopen it works.

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In my case I have the same script running on 3 computers. On one it never happens. On the second it happens 3 times per day and on the third it happens every time I run it. Closing the browser and reopening fixes it temporarily.

I am wondering if AVG antivirus is the culprit. That’s the main difference between the first machine and the other two.

Please see Error #101 Solution