You may experience the following symptoms either in Microsoft Outlook in Online mode or in Outlook Web App (OWA) when the mailbox is located on a server on which Exchange 2010 Service Pack 2 RU6 or Exchange 2010 Service Pack 3 has been installed:
You cannot soft delete messages that contain voice mail attachments.
You cannot soft delete messages that have attachments (such as a PDF file) that are sent from a FAX server, a printer, or a scanner.
Note This issue does not occur if the message is sent by a user instead of by an application, or if the message has no attachments.
This issue occurs after Exchange 2010 Service Pack 2 RU6 or Exchange 2010 Service Pack 3 is installed.
To resolve this issue, install the following update rollup:
2803727 Description of Update Rollup 1 for Exchange Server 2010 Service Pack 3
Workaround 1: Hard delete the message instead of soft deleting
To hard delete email messages in Outlook, select the message, and then press Shift+Delete.
Workaround 2: Use cached mode for Outlook
When you use the cached mode of Outlook, the message can be soft deleted. For more information, go to the following Microsoft TechNet topic:
For more information about how to recover deleted messages in Microsoft Exchange 2007 or Microsoft Exchange 2003, click the following article number to go to the article in the Microsoft Knowledge Base:
246153 How can I recover items that I have "hard deleted" in Outlook?
For more information about how to recover deleted messages in Microsoft Exchange 2010, go to the following Microsoft TechNet website: