The correct attribute should be 'nameConflict' as documented here in Lucee and ACF. https://docs.lucee.org/reference/functions/fileuploadall.html https://helpx.adobe.com/coldfusion/cfml-reference/coldfusion-functions/functions-e-g/fileuploadall.html https://helpx.adobe.com/coldfusion/cfml-reference/coldfusion-functions/functions-e-g/fileuploadall.html