Answer

1. Start by unpacking the workbook per the steps at Unpackage a .twbx in Tableau Help. 
   1. Depending on the data source your workbook connects to, this may be all you need to do. For example, if the data source is an Excel file, it can be opened directly to see the data. 
   2. Most likely, the data source will be a Tableau Extract file type, which only opens in Tableau Desktop.  In this case, the following steps should allow you get the non-updated data. 
2. Open the original packaged workbook(.twbx) in Tableau Desktop.  
3. Click on the Data Source tab at the bottom left of Tableau Desktop to see the data source and tables. 
4. Change from a live connection to extract in upper right.
5. In the left "Connections" pane, mouse over the data source that you want to get the old data for, and a black arrow should appear, click the arrow.
6. Select "Edit Connection."  This opens the file browser to find the new data source, and defaults to the Tableau Repository Folder.
7. Navigate to the folder that contains the data source, which was created when doing the unpackage above, and select the data source.
8. The workbook should show the old data as it was. To save a copy of this in an excel spreadsheet, click on a sheet in Tableau Desktop.  In the "Data" pane, right click the data source, and select "Export Data to CSV."  Select a save location and name the file, then click save. 

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