Error: "Errors occurred while loading the data source" When connecting to Excel files

Option 1 - Possible corrupt file

1. Open the affected Excel file.
2. Copy the entire data in the file.
3. Paste the data into a new Excel file.
4. Save this new Excel file.
5. Connect Tableau Desktop to this new Excel file.

Option 2 - Has the file path changed?

Tableau Desktop:

1. Open the Tableau Desktop workbook.
2. Right-click on the data source in the Data pane on the top left of the window and select Edit Data Source... 
3. Click on the Excel file name and ensure that the connection is pointing to the right file path. This option can be found under Connections > <data source> drop down menu > Edit Connection...
4. If the file path is wrong, then re-establish a connection to the Excel file located at the correct file path.

Tableau Server/Cloud:

It is important to understand if the data has been published separately or when the data is embedded in a published workbook.

If the data is published separately, you can use the "local copy" method outlined in this KB article on Editing a Published Data Source, to determine the path of the file and make any adjustments needed and then republish the data source. 

If the data is embed in a workbook, download the workbook from Tableau Server or Tableau Cloud and perform the steps in Option 2 and republish the workbook.

Option 3 - Old file type

If using a file created in a very early version of Microsoft Excel, we will need to change the file extension from .xls to .xlsx.  

1. Open the Excel file in Microsoft Excel, and then save it with the .xlsx extension.  
2. Open Tableau Desktop, Tableau Server or Tableau Cloud and reconnect to the .xlsx file.