Error "Bad Connection: Tableau could not connect to the data source" When Opening a Second Tableau Desktop Instance

Published: 31 May 2018
Last Modified Date: 21 Apr 2020


When trying to connect to a data source in a second instance of Tableau Desktop (while another session is already running), one of the following error messages occurs:

An error occurred while communicating with Tableau Data Engine. Bad Connection: Tableau could not connect to the data source. There was problem and the data engine could not start properly.

Dashboard unavailable
There was a problem connecting to the "<data source name>" data source

In addition, Tableau Desktop may attempt for some time to connect to the data source with a window with the title "Processing Request" and the message, "Connecting to database..."
If Cancel is chosen, The message "Cancelling" may be displayed for several seconds before resuming the "Connecting to database..." message. This can happen repeatedly.


  • Tableau Desktop 2018.1 - 2018.3
  • Windows
  • File-based data source (.csv, .xlsx)


Work with your IT team to ensure that your computer is up to date with all Windows updates.


The necessary Windows Updates are not installed on the affected computer.

Additional Information

The information below is related to a third-party product. Please note that while we make every effort to keep references to third-party content accurate and up to date, the information we provide here might change without notice as the third-party product changes:

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