Consider the following scenario:
You request a read receipt for all sent email messages in a Microsoft Exchange Server 2010 Service Pack 1 (SP1) environment.
You send a meeting request to a recipient.
The recipient accepts the meeting request.
In this scenario, you receive the following non-read notification (NRN) unexpectedly after 120 days have passed:
Sent: <Date, Time>
Subject: Not read: <Subject>
Your message was deleted without being read on <Date, Time>.
This issue occurs because the SuppressReadReceipt flag is not used when the Microsoft Exchange Mailbox Assistants service deletes the expired calendar items. The calendar logging feature generates messages in the recoverable items root folder when a user accepts a meeting request that includes a read receipt.
After 120 days, the Microsoft Exchange Mailbox Assistants service deletes the messages in the recoverable items root folder. This generates one or more NRNs if the SuppressReadReceipt flag is not used.
To resolve this issue, install the following update rollup:
2608646 Description of Update Rollup 6 for Exchange Server 2010 Service Pack 1
Note The NRNs are not completely flushed until 120 days have passed after the hotfix is installed.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about notifications when other users receive or read an email message, visit the following Microsoft website:
General information about notifications when other users receive or read an email messageFor more information about the SuppressReadReceipt flag, visit the following Microsoft website: