I experienced this error using OutSystems Service Studio 10.0 where I have an input parameter with a datatype of a record (a table in my database). I wanted to use some fields on this input parameter for an aggregate query inside the web block screen preparation, but the problem is when I open the aggregate and add some filters the input parameter is not found in the local variables. This aggregate is querying the same table which is the data type of the input parameter. The problem What seems to be the problem was, the input parameter is named exactly the same with the name of its table (which is the data type of this input parameter), so I tried changing its name by just adding a "Rec" to it, and it worked. Solution The solution is to rename the input parameter so that it will not be the same with the exact table name of any tables in your aggregates.