MailStore – When deleting messages from Exchange mailboxes, Exchange may send notifications to the sender of the message
Summary
If you archive Exchange mailboxes, disposition notifications (“Your message was deleted without being read”) are sent to the sender of the emails being archived.
Cause
Microsoft Exchange sees MailStore as an email client, therefore when messages are deleted the disposition notification mechanism is trigger. This is intended behaviour in Microsoft Exchange.
Resolution
This behavior of an Exchange Server is triggered when you have a MailStore Exchange-type archiving profile with both the “Delete messages…” and “Also archive unread messages”.Since these notifications are normal emails that are sent through Exchange as usual, their delivery can be suppressed through a transport rule.
Microsoft 365 mail rules are described in Microsoft article Mail flow rules (transport rules) in Exchange Online.
Exchange Server 2013 through 2019 use the Exchange Control Panel (ECP) for configuration, go to Mail Flow > Rules.
For both Microsoft 365 and Exchange 2013-2019, you will use these settings in the mail flow rule:
- Set the message type to “Read Receipt”.
- Depending on your environment, filter the subject for “Not read”, etc.
- In addition, you can filter the message subject and body for “message was deleted without being read”
- As action choose “Delete the message without notifying anyone”.
Exchange Server 2010 and newer can identify and drop such emails effectively through filters. In Exchange Server 2010 the rules can be found under Organization Configuration > Hub Transport > Transport Rules.
In Exchange Server 2007 the rules can be found under Organization Configuration > Hub Transport > Transport Rules.
Additional Information
Message Disposition Notifications are more commonly known as read receipts and there is more information about their functionality and implementation in an Exchange Team Blog article.