How to tell if an email is tracking you, and how to stop it

Most marketing email carries a tiny remote picture that reports when you open it, and links that record a click before they take you on. Stop pictures loading by themselves in your mail program, read suspect mail as plain text, and leave lists you never asked for with the List-Unsubscribe link, not by replying.

30 October 2026 · 4 min read

How open tracking works

A tracked email contains a picture, often one pixel and invisible, fetched from the sender’s server with an address made for you alone. When your mail program loads it, the server learns that this message was opened, when, roughly where from (your internet address), and often which program you use. Open it twice and it knows that too.

Clicks are tracked a second way. A link that says one shop’s address may first go through the mailing company’s server, which records the click and then sends you on. Hover over the link to see where it really goes.

How to tell

Pictures you did not see load. If your program says it blocked pictures or remote content in a message, something in it was going to be fetched from outside.
Links through another address. A link to example-shop.com that hovers as click.mailer.example/abc123 is a tracked link.
The message source. View source (Show original in Gmail) and look for image addresses with long codes in them.

Almost every newsletter does this. It is how senders measure open rates, and the law in the UK and EU treats it like a cookie that needs consent, which many senders gloss over.

Stopping it in common mail programs

Outlook for Windows does not download pictures automatically for most senders; leave it that way in File, Options, Trust Center, Automatic Download.
Gmail fetches pictures through Google’s own servers, which hides your address but still tells the sender you opened it. Settings, General, Images, “Ask before displaying external images” stops that.
Apple Mail on recent Macs, iPhones and iPads has Mail Privacy Protection, which fetches remote content privately in the background, so an “open” no longer means you read it.
Thunderbird blocks remote content by default and shows a bar to allow it per message or per sender.

Reading a message as plain text shows no pictures at all, which is the surest way to read something you do not trust.

Leaving a mailing list safely

Proper bulk mail carries a List-Unsubscribe header, which most mail programs turn into an Unsubscribe link at the top of the message. Since 2024 Gmail and Yahoo have required large senders to offer a one-click version of it and to act on it within two days. Use that rather than replying.

Use it for mail from a company you recognise and once gave your address to. For outright spam, do not click anything: the click confirms your address is real. Mark it as spam or junk instead.

Our own product, disclosed

Where our own software comes into this

We make Rutba Office, a free desktop suite for Windows. Its Mail app keeps tracking pictures from loading and shows which ones it stopped and where they would have come from. A message can be read as plain text, and the sender’s details checked before trusting it. Where a list offers the standard unsubscribe, Mail does it in one click with a confirmation, and a list message with no way off can be marked as bulk mail.