Error "An error occurred when running the flow" When Joining with Concatenated String in Tableau Prep

Published: 29 May 2019
Last Modified Date: 30 Jul 2019


After creating a join node with a concatenated String on one side of a join clause in Tableau Prep (note that both sources are Excel), then the following error might occur: 

An error occurred when running the flow.


  • Tableau Prep 2019.1.4 and earlier
  • Excel


Option 1

Upgrade to Tableau Prep version 2019.2.1 or a later version. For additional information about upgrading, see the following Tableau Help articles: 

Option 2

Alternatively, use one of the following temporary workarounds :
  1. Create an extract of the data before performing the join
  2. Create the required field in Excel before importing to Tableau: CONCATENATE function
  3. Use the “Preview in Tableau Desktop” option to view data


This issue (ID: 898098) has been fixed in a newer version of Tableau Prep.
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