I was able to successfully recall a message using Microsoft Outlook but I am worried that the recipient still read the email. His email would have been open when I recalled it but he was not using it, and I did get a recalled successfully message.

In another case I received a recall notice from someone who had sent a message to me (while my email was not running) and I was able to read the recalled message.

I just want to clarify.

Recall? Like you didn't want the recipient to read it? I'm sorry, but I've never heard of that.

If you received a successful recall message from the Exchange server than you have to assume that the email never reached the destination.

When you receive an attempt to recall a message it means that the sender was unsuccessful because the message has already reached your Inbox.