This invention relates to compositions of matter, methods, modules and instruments for automated mammalian cell growth and mammalian cell transduction followed by nucleic acid-guided nuclease editing in live mammalian cells. The present compositions and methods entail viral delivery of an editing cassette to live mammalian cells such that the editing cassettes edit the cells and the edited cells continue to grow, preferably using a fully-automated end-to-end instrument to process the cells without human intervention to enhance cell processing uniformity and to maintain the integrity of the cell culture.