Understanding Problem Error Handling Loop

Hello all,

I have an understanding problem.

A Table Row to Variable Loop should not stop on an error, but continue with the next number.
I would like to write the respective “identification number” and the error in a separate table.

I have already tried a few combinations today with Try (Data Ports) and Try (Variable Ports), but couldn’t get it to work. Maybe someone can help me here.

I have attached an example workflow without errors.
Example Workflow for Knime Hub Question.knwf (1.3 MB)

Thanks and greetings


Hallo Zusammen,

ich habe ein Verständnisproblem.

Ein Table Row to Variable Loop soll bei einem Fehler nicht stoppen, mit der nächsten Nummer weitermachen.
Die jeweilige „Identifizierungsnummer“ und den Fehler würde ich gerne in eine seperate Tabelle schreiben.

Ich habe heute bereits einige Kombinationsmöglichkeiten mit Try (Data Ports) und Try (Variable Ports) ausprobiert, aber es nicht hinbekommen. Vielleicht kann mir hier jemand weiterhelfen.

Ein Beispielworkflow, ohne Fehler habe ich angehängt.

Example Workflow for Knime Hub Question.knwf (1.3 MB)

Danke und Grüße


@robbsen I once built a workflow to handle such a problem but could not immediately adapt it to your question. Will see if I can can do that:

@robbsen OK I think I built something you might be able to work with. The important points are:

  • encapsulate your loop in a component. Otherwise KNIME seems to have a problem to identify the Try-Catch block
  • provide an empty table with the same structure as the one you want to collect at the end of a loop. I think you also could just use one table with one column and allow changing data structures in your Loop-End (you might have to clean that up later)
  • I have not fully worked out the use of the error messages. In this case it just checks which ID ‘made’ it thru and would list the ones who did not


With the dummy data, it definitely looks like the solution. I’m curious if it will work with the real data in the new year.

Will report in any case.

Thank you very much for helping me

Learned a lot again.


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