I've created a tableau TDE file that I've been using regularly- now when I when doing a totally normal data query the view data icon then hit the "underlying data" tab I get the error message "An error occurred while loading the data" an offers a "show details" button. When that button is selected I get: Invalid expression, cannot be unaggregated- anyone know why this is happening?
digging on the tableausoftware.com forum, I found that sets could lead to this error. I had just created a couple of sets in my workbook prior to this issue. Once the sets were deleted- things worked again. I was able to see the underlying data.