Electronic reporting (GER) framework allows for an application specialist to bring to GER model mappings references to required business data (tables, data entities, queries, etc.) introducing them as data sources. Whenever business data from underlying tables, entities or queries must be transformed by using grouping and aggregation, new data sources of the GROUPBY type are added. The error “Unable to cast object of type 'Dynamics.AX.Application.ERModelGroupByDataContainer' to type 'Dynamics.AX.Application.ERIDataContainerList'” may occur when the list of records from such GROUPBY based data source is used in executing GER reports.