Consider the following scenario:
- You have a computer that is running Microsoft Exchange Server 2007.
- User A sends an email message to User B and selects the "Request a read receipt for this message" option.
- User B deletes this email message without reading it.
In this scenario, if User A accesses his mailbox by using Microsoft Office Outlook, he receives the following read notification:
Your message was deleted without being read.
However, if User A accesses his mailbox by using a third-party application, he receives the following read notification:
The message was not read because it expired before reading at time.