In order to open an attachment from within Outlook 2013 I have to open the "Enterprise Vault" tab and then use the "Vault Search" feature. Approximately a week ago we were able to open attachments from within Outlook 2013 simply by opening the message from the fault and then clicking on the attachment. At the present time when I open the message there is no attachment, only text at the bottom of the message indicating the name of the attachment. (that is not able to be opened).
Client version: Symantec Enterprise Vault Outlook Add-in 22.214.171.12406
From what I understand, you are not able to open archived emails by double-clicking the shortcuts within MS Outlook, but you are able to access the emails via EV Search.
This may be related to an MS security patch update. We have seen many customers affected by this. Have a look on this article for the solution: https://www.veritas.com/support/en_US/article.000127958