Consider the following scenario:
- You are in a Microsoft Exchange Server 2010 Service Pack 3 (SP3) environment.
- You install Active Directory Rights Management Services in the environment.
- You create an email message in Outlook Web App, attach an incorrectly formatted file, and then set the Do not forward permission. For example, you change a file that has .txt extension to .docx, .pptx, or .xlsx extension, this causes the file to be formatted incorrectly, and then you attach the file to the email message in Outlook Web App.
This issue occurs because Office protector encrypts an attachment file even though it is in an unknown format.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.