Unable to Refresh Data Validation Group Results Due to Error: 

Email Error: 

Unable to Update Data Validation Results: [VID HERE]. Error: Conversion from type 'DBNull' to type 'String' is not valid

NOTE: The number listed in the email corresponds to the ID of the definition causing the error

Cause

Data Validation Definition results in a NULL value in the Description column, usually due to a CASE statement without an ELSE clause.

Resolution

Adjust the query definition so Description never returns a NULL