Error "Communication with the Tableau Protocol Server process was lost" When using Teradata ODBC Driver

Published: 19 Jan 2019
Last Modified Date: 17 Apr 2019


When creating or refreshing an extract based on a Teradata connection, the following error occurs in Tableau Desktop and Tableau Server:

ExternalProtocol::PipeMessageSource::ReadBytes: Communication with the Tableau Protocol Server process was lost.

In addition, Tableau Desktop will display a prompt to reconnect.


  • Teradata 16.20.0.x driver
  • Tableau Desktop or Server installed on a machine using comma as decimal separator (Most European locales, including German, French, Spanish...)
  • High precision columns (Decimal (16,#) or higher)


Try one of the following workarounds: 

Workaround 1

  1. Use the attached TDC file.
  2. This TDC will tell the Teradata driver to ignore the machine regional setting.
  3. Please note that is the extract is published, a matching TDC file will need to be in Tableau Desktop and Tableau Server repository and the extract will need to be republished using the TDC file.
Important: Tableau does not test or support TDC files. These files should be used as a tool to explore or occasionally address issues with your data connection. Creating and maintaining TDC files requires careful manual editing, and there is no support for sharing these files.

Workaround 2

This issue only affects Teradata ODBC drivers 16.20.X. Uninstalling 16.20.X and installing any of the previous version (15.00.X, 15.10.X, 16.10.X) will resolve the issue.

Workaround 3

  • Creating a DSN for Teradata. In the DSN configuration, uncheck the box for Use Regional Settings for Decimal Symbol.
  • To connect using a DSN, please select the Generic ODBC connector in Tableau Desktop instead of the Teradata connector.

Workaround 4

Change the regional settings on the machine running Tableau Desktop or Tableau Server to use a dot as decimal separator.

Workaround 5

In Teradata, change the data type of the column to NUMBER(16,4) instead of DECIMAL(16,4)


  • This behaviour is related to a known issue with Teradata drivers 16.20.
  • The issue occurs when Tableau is installed on a machine using comma as decimal separator and queries a field that has a datatype Decimal (16,#) or higher in Teradata.
  • Teradata is aware of the issue and are working of a fix for a future version, contact Teradata's Support team for more information. 
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