Error "sqlserver is not supported by this version of Tableau"

Issue

When opening a packaged workbook with SQL Server as the underlying data source, the following error may occur:

sqlserver is not supported by this version of Tableau. Error Code: A7AE0C94

Environment

Tableau Reader 2020.4.0
Microsoft SQL Server

Resolution

Update to the latest Tableau Reader version, which can be downloaded from this page.

If it is not possible to update Tableau Reader, try the following workarounds:
Option 1:
Launch Tableau Reader from the command line using the following command

tabreader.exe -DOverride=ModularDialogUsingAdapter:off

Option 2:
Try the following workaround to allow the Tableau Reader 2020.4 users to open the workbook:

Make a copy of an affected workbook.
In File Explorer, navigate to the folder containing the workbook file. If the .twbx file extension is not visible, select the option on the View tab in File Explorer.
Right-click the .twbx file, select 'Rename' and change the file extension to .zip.
Right-click the .zip file, and select 'Extract All' > 'Extract'.
Open the extracted folder, and navigate to the Data\Datasources subfolder.
Open the .twbx file in Tableau Desktop.
Drag the .hyper file from the Datasources subfolder in Step 5 onto the Tableau Desktop window. You should see the Data Source page with the direct extract file connection.
Navigate to one of the sheets in the workbook by clicking its tab.
Right-click the original data source in the Data pane, and select 'Replace Data Source'.
In the Replace Data Source dialog, click 'OK'.
Right-click the original data source, and select 'Close'.
Save the .twbx file. You should be able to open this file in Tableau Reader 2020.4.