I am receiving the same cryptic error message: "Invalid expression, cannot be unaggregated", when trying to connect to a table within Tableau. In my case I am attempting to connect to a straightforward MS SQL table, only 21 fields. Did you ever figure out what the source of the error message was in your case?
A few steps to try.
1) Examine the logs to see if there is anything informative related to the data source in there. Logs are created in the \logs directory of your Tableau Repository folder (typically in the Documents folder of a Windows PC).
2) verify the correct drivers are installed - Drivers & Activation | Tableau Software
3) verify access to the data source with another tool (MS SQL tables can be attached to with Excel and Access).
If none of these options lead to a resolution or at least a more definitive cause, please contact firstname.lastname@example.org. Remember to pass along the version of Tableau Desktop in use as well.
Hope this helps,
Hey Robert, did you resolve your issue connecting to a table? I am receiving the same issue when using an extract (created from Excel). The extract pulls all the correct data (validated by the visual results) however I am unable to see any of the data, It gives me the same error message you were receiving.
Any help would help
I had the same issue and worked with support. This is the answer they sent me and it seems to have fixed the problem.
"The 'Invalid expression, cannot be unaggregated' error message is occurring because there are sets being used in the calculated fields. The data for these fields cannot be disaggregated which keeps Tableau Desktop from being able to calculate the underlying data of the worksheet.
One possible workaround for this would be to make a second connection to the data source from which these fields originate and then rebuild the worksheet using the duplicated data source. Then use the new duplicated connection to build the desired worksheet and remove the sets from the primary data source. This would allow viewing the underlying data in the other worksheets while still allowing the worksheet to be built. "
Nice to Share the solution which was solved by TABLEAU SUPPORT TEAM