64% of apparent email opens were Apple Mail prefetches, and link scanners inflated clicks

Open rate is the metric most cold-email tools steer by. At the group, raw open rates of 2.3–3.8% looked like a deliverability signal worth optimising.

Apple Mail Privacy Protection fetches images on a recipient's behalf, and security scanners follow links, so a recorded open or click can be a machine.

• A cohort analysis of the campaign database that separates opens by user agent: Apple's prefetch proxy (a bare "Mozilla/5.0") against identifiable mail clients.
• Click-through measured per cohort, plus a filter for link-scanner clicks.
• A written runbook for recognising bot opens and clicks, so campaign results are read from the cleaned numbers.

• Of 711 opens that looked genuine, 455 (64%) were Apple Mail Privacy Protection prefetches.
• Raw open rates of 2.3–3.8% corresponded to a real human rate of 0.6–1.4%.
• Mail opened by Apple's proxy clicked at 0.52%; identifiable mail clients clicked at 8.33%.
• Link scanners turned 437 recorded clicks into fewer than 10 humans.

• This describes one client's sending programme, from its campaign database. It is not a statement about email in general.
• We did not measure any revenue effect. The finding is that the dashboard metric overstated engagement.