Some users are not receiving email open events on the campaign delivery report even after opening the email. This issue is caused by Apple caching the email's images on its server and marking it as "opened" even if the recipient has not viewed it yet. This feature was specifically developed to protect user privacy by undermining email tracking pixels. Your email open rates could be affected depending on how many users have enabled this feature and how many of them use the Apple Mail App.

Resolution

Please note the following suggestions for improving engagement rates in your email campaigns:

1. Include links to other relevant content in your email campaigns. When recipients click on these links, their actions will be counted both as a click and a unique open. For more information on this strategy, please see the "Email" section of the Engagement Rate article.
2. Use an acknowledgment feature for important or required reading. This feature ensures that users have viewed the content in its entirety and requires them to confirm their understanding. Please note that this feature should only be used for critical information, not general updates. For further guidance on using acknowledgment features, please refer to the Acknowledge Setting article.
3. Standardize on an email client that does not interfere with email tracking pixels. Some email clients, such as Apple Mail with the MPP feature enabled, do not count "machine_opens" and can artificially inflate open rates. It's important to select an email client that allows for accurate tracking of email engagement.