 He received a BSc degree from the University of Otago in 1956, and two years later an MSc for his work on mycorrhizae morphology in native New Zealand plants.In 1961, having been awarded a National Research Fellowship the year before, McNabb left New Zealand for the UK to study with Cecil Terence Ingold at Birkbeck College.McNabb earned a PhD in 1963; his thesis was titled "Taxonomic studies in the Dacrymycetaceae".