There is, however, a way to know for sure. Eudora can request a return receipt for you. If the recipient's email client supports return receipts, too, and if it's okay with the recipient, you'll get an email back certifying that your message has been opened, when it has been opened.
Request a Return Receipt in Eudora
To request a return receipt with Eudora:
- Make sure the Return Receipt button is clicked while composing a message.

