This issue occurs when you try to restore archived email messages into your mailbox and view the email messages through Microsoft Outlook. For example, originally, the rich text message contains inline images in the body. After restoring it in Microsoft Exchange Server 2013, the message is displayed in HTML format, but the images are not shown. Outlook indicates that the message has an attachment. However, it cannot be displayed.
This issue occurs because Microsoft Outlook message format (.msg) files change format when you copy them into an Exchange Server 2013 mailbox.
To resolve this issue, install Cumulative Update 9 for Exchange Server 2013.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.