Error "System error: An error occurred while communicating with data source 'LoomDataSource'" And "Multiple entries for column [ColumnName]! " Running Salesforce Flows After 2022.4 Release

Published: 01 Dec 2022
Last Modified Date: 17 Jan 2023


When running Salesforce flows jobs after the 2022.4 release, the following error occurs: 

System error: An error occurred while communicating with data source 'LoomDataSource'

The following error will be produced in the logs: 

Multiple entries for column [ColumnName]! The metadata key is: [ColumnName] and the class type is: [column], the existing class type is: [column]


  • Tableau Cloud
  • Tableau Server
  • Tableau Prep
  • Salesforce


As of 1/12/2023, Tableau Cloud will no longer experience this issue.  If using Tableau Server and need a workaround to the issue, use one of the following options:

Option 1

Manually run the flow in Tableau Prep Builder version 2022.3 or earlier. 

Option 2

Script the job to run using the Prep Command Line Utility.  See Refresh flow output files from the command line for details. 


This issue is currently being addressed in Known Issue ID 1487701.  Tableau Cloud has been updated to include the fix on 1/12/2023.
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