Error "Refresh failed (Unknown failure)" Refreshing SQL Server Extract on Tableau Server

Published: 13 Dec 2013
Last Modified Date: 14 Aug 2020


Scheduled extract refreshes of Microsoft SQL Server data source might fail on Tableau Server, and the following error might appear in the background tasks view:
Refresh failed (Unknown failure) Tableau Data Engine Error: 4: SimpleDatabase::SelectMetadataName: expected found=1, actual found=0 (fk=18446744073709551615 name="Extract" nameTable="SCHEMAS")
When trying to refresh the extract on Tableau Desktop, the refresh succeeds.


  • Tableau Server 
  • Microsoft SQL Server


On the computer running Tableau Server, download and install the Microsoft SQL Server driver from the Drivers & Activation page.


The necessary Microsoft SQL Server driver is not installed on the computer running Tableau Server.
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