I am trying to run native QGIS functions through python (programatically) while exporting the output in two different ways : Exporting output into a physical file : processing.run("qgis:listuniquevalues",\ {'INPUT': vlayer,\ 'FIELDS' :'Rendement',\ 'OUTPUT': output_path+'channay_Rendement_unique.shp'}) Exporting output into memory (virtual layer) : processing.run("qgis:listuniquevalues",\ {'INPUT': vlayer,\ 'FIELDS' :'Rendement',\ 'OUTPUT': 'memory'}) I then try to visualize the result layer...