How to prevent tracking of your emails

All those nasty marketing emails popping up your inbox don’t just promote a product. They also monitor if you opened the email, when you opened it, and where you were at the time by using software like MailChimp to embed tracking software into the message.

How it works? A single tracking pixel is embedded in the email, usually (but not always) hidden in an image or link. When the email is opened, the code in the pixel sends the information back to the company’s server.

There have been some attempts to limit the amount of information that can be transmitted in this way. For example, since 2014, Google has served all images through its own proxy servers, which could hide your location from at least some tracking apps. And extensions like Ugly Email and PixelBlock have been developed to block trackers on Chrome and Firefox.

There is also a simple basic step that you can take to avoid trackers: prevent your email from automatically loading images because the images are where the majority of those pixels are hiding. You won’t be able to avoid all the trackers that may be hiding in your email this way, but you will stop a lot of them.

Here’s how to do it in major desktop and mobile messaging apps:

Disable automatic loading of images in Gmail:

• Click on the gear icon in the upper right corner to access your settings, then click on “Show all settings”.
• On the “General” tab (the first one), scroll down to “Pictures”.
• Select “Ask before viewing external images”.
• Scroll to the bottom of the page and click “Save Changes”.

Note that this will also turn off Gmail’s dynamic messaging feature, which makes emails more interactive.

Disable automatic loading of images in Microsoft Outlook (Office 365):

• Click “File”> “Options”.
• In the “Outlook Options” window, select “Trust Center”.
• Click on the “Trust Center Settings” button.
• Select the check boxes “Do not automatically download images in standard HTML messages or RSS elements” and “Do not download images in encrypted or signed HTML e-mails.” You can make a number of exceptions to the first item if you wish by checking the boxes below.

Disable automatic loading of images in Apple Mail:

• Select “Mail”> “Preferences”.
• Click on the “View” tab.
• Uncheck “Load remote content in messages”.

Disable automatic loading of images in Android Gmail:

• Tap the three lines in the upper left corner.
• Scroll down and select “Settings.”
• Tap the email account you want to work with.
• Scroll down and select “Pictures”.
• Tap “Ask before viewing external images”.

Disable automatic loading of images in iOS Gmail:

• Open Gmail for iOS, tap the hamburger menu at the top left, and scroll down to settings.
• Tap the account you want to personalize, then tap “Pictures.”
• Change from “Always show external images” to “Ask before showing external images”.

Note that for those who want to do this on Gmail’s mobile client, it looks like it will only work for personal accounts and not for corporate accounts managed through G Suite, at this time.

Disable automatic uploading of images to iOS Mail:

• Tap “Settings”> “Mail”.
• Find the “Messages” section and turn off the “Load remote images” option.

Another option is to use an email client such as Thunderbird, which blocks remote images by default; the app allows you to download embedded content on an individual basis or allow the images of contacts you trust not to send any code hidden in their images.

Update July 3, 2019 at 3:47 p.m. ET: This article has been updated to include additional information about email clients.

Update September 3, 2019 at 7:35 p.m. ET: This article has been updated to include instructions for turning off automatic image uploading on Gmail for iOS.

Updated February 17, 2021, 5:30 p.m. ET: The instructions for Microsoft Mail have been removed and some instructions have been updated.