Apple Mail Privacy Protection (MPP) is a setting in Apple’s Mail app that downloads the images in every email, including the invisible tracking pixel, through Apple’s own servers before the reader has looked at the message. Senders therefore record an “open” whether or not the person read it, and cannot see the reader’s real IP address or location.
How Apple Mail Privacy Protection works
Email platforms count an open when a tiny image unique to each recipient, a tracking pixel, is fetched from their server. Apple introduced MPP in 2021 with iOS 15 and macOS Monterey. When a Mail user turns it on, which the app invites them to do, Apple fetches remote content through proxy servers, generally soon after the message arrives rather than when it is read.
The pixel loads, the platform logs an open, and the time and place attached to it describe Apple’s infrastructure rather than the person. The setting belongs to the Apple Mail app on iPhone, iPad and Mac, whatever the address behind it, so a Gmail or Outlook account read in Apple Mail is affected too. Someone reading Gmail in the Gmail app, or a work account in the Outlook app, is not.
Clicks are unaffected. A click still needs a person to tap a link, so click data remains the most dependable sign of attention.
Why it matters for a UK business
Apple devices are common among UK email readers, so on many consumer lists a large slice of recorded opens is now automatic. Your open rate looks healthier than it is, and anything built on opens inherits the error:
- Subject line tests decided on opens pick a winner more or less at random.
- Re-engagement and sunset rules that count an open as activity keep people on the list who have not read anything in a year.
- Send time optimisation learns from when Apple fetched the email, not when people read it.
- Location and device reports lean towards Apple’s servers.
- Live content such as countdown timers can be frozen at the moment of the prefetch.
The damage goes beyond reporting. Mailbox providers judge your sender reputation partly on whether recipients engage, and a list padded with people who never read anything gradually drags down your deliverability.
Common mistakes
- Reporting open rate to the board as if nothing changed in 2021.
- Comparing this year’s open rate with figures from before MPP and calling the rise an improvement.
- Defining an engaged subscriber as anyone who opened in the last 90 days.
- Letting the email platform choose A/B test winners automatically on opens.
- Assuming the effect is limited to people with Apple email addresses.
How to act on it
At the time of writing (October 2026), most major email platforms flag opens they believe came from MPP, sometimes labelled machine opens or Apple privacy opens. Find that setting and exclude those opens from engagement segments and reports. Then move your key measures to clicks, a click-to-open rate worked out on human opens only, orders, enquiries and revenue per recipient.
Rebuild your definition of an engaged subscriber around clicks, purchases, replies and site visits from email. Run subject line tests on clicks or conversions, accepting that they need bigger samples. Keep opens only as a rough alarm: a sudden fall at one mailbox provider still suggests your mail is being filtered there. If you are deciding how email should be measured next to your other channels, that is part of the digital marketing strategy work I do.