This document describes further detail in regards to the "This envelope is damaged and cannot be opened" error message received when you use the Cisco Registered Envelope Service (CRES) through a Cisco Email Security Appliance (ESA).
How do I correct the "This envelope is damaged and cannot be opened" error?
When you open CRES encrypted messages which contain attachments in Microsoft Internet Explorer and you use Oracle Java, you might receive this error:
This envelope is damaged and cannot be opened (the Java
console may provide more information). Please contact
the sender for a replacement envelope.
Earlier versions of Java based Envelope Tools that are used to open encrypted messages with attachments might present this issue. This was identified in Cisco bug ID CSCuj26423. End users can work around the problem with use of the "Open Online" link as presented from the original message or the ESA administrator can suppress the Java applet in the advanced section of their encryption profile.
Choose Security Services > Cisco Ironport Email Encryption > Select the encryption profile > Advanced.