Our tracking works by embedding an unique tracking pixel into the bottom of your email message. When a recipient opens your email, the tracking pixel will load and we will record an 'open' event.
For our tracking to properly record an 'open' event, the recipient would need to open the message and load the unique tracking pixel. If the recipient's email settings are to not display images, the message can be opened and read without loading the tracking pixel. We are able to track the reply that is received as that data originates from your inbox once the message is sent to you.
Unfortunately, there is not a good solution to this issue as it is based on the email preferences of the recipient. We find that it is rare that recipients have chosen not to display messages but it does happen.
When you send an email to several people, CC someone on an email, or if the message gets forwarded, we can only tell you that ‘somebody’ opened your message.
Learn more by reading our post about Yesware email tracking. When in doubt, you can always test tracking by sending an email to firstname.lastname@example.org.