When you copy Microsoft Outlook message format (.msg) files into a mailbox in a Microsoft Exchange Server 2013 environment, you receive the following error message:
Customer OPENTEXT has issues with mails stored as MSG files, to restore into an Exchange 2013 mailbox.
This issue occurs because of the design function logic with message body preview.
To work around this issue, delete the PR_RTF_IN_SYNC property of the affected email messages. After that, the messages that are saved as .msg files can be copied into a mailbox in Exchange Server 2013.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.