File Reader BUG: Supply file path via Variable works for configuration, execution fails

  1. Giving a file path such as /Users/qqilihq/Desktop/data.csv via flow variable to “File Reader”
  2. File gets loaded, I can make my configuration, click OK
  3. Execution of the node fails with error message “Cannot create URL of data file …”
  4. Why does the node then accept a file path at all for configuration?!

Edit: At least, file:/ URL works for configuration AND execution.

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Hi @qqlihq,

Thank you – what KNIME version are you using? 4.3?

For the file reader, the expected flow variable containing the file location should include file:/ URL.

Best wishes


Then why does the configuration window allow inputting a simple file path at all? Why does the preview appear and everything seems like it works, and the node only fails on execution?

@qqilihq (Hi :slight_smile: ) so this is in the nightly build?

My apologies! – No, it’s 4.2.3.

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Hi @qqilihq

Good questions :slight_smile:

So, while configuring, the node takes the normal path (as the user selects using the browse button). Then, internally, to execute, the node needs the URL. That is why the path would work when configuring the node, but it does not work to execute.

In the new simplified file reader node, this is actually different and it works as you would expect, taking the file path.

Hope this helps!


Thanks, @ana_ved & @Iris – looking forward to that new node! (I still feel this should be fixed in the old node, as it causes confusion and I’ve just today spotted a very similar question here on the forum about this)


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