Since being discovered in 1993, microRNAs have gone on to win a Nobel Prize in Physiology or Medicine, thanks to private sector uptake with the COVID-19 vaccines that saved the world during the pandemic that emerged from Wuhan, China in early 2020. Errors in the manufacture of over 1,000 microRNAs can put us at risk for developmental disorders, cancer, or neurodegenerative disease and a new study looks at a molecular machine called Microprocessor (MP), which trims longer molecules called primary microRNAs (pri-miRNAs) - without cutting other kinds of RNA that resemble pri-miRNAs.