This issue occurs when the PR_Body_HTML MAPI property within that message is incorrectly copied when creating the Vault Cache using Outlook 2013 on The Vault Server in an Exchange 2010 environment. The result is that the message is rendered in text format and not HTML. It has been determined that this incorrect copying of the PR_BODY_HTML occurs when Outlook 2013 is creating the VaultCache files and transferring to the user's workstation.
Problem PR_BODY_HTML in Vault Cache:
Hi all,
What do you think?
Manager
www.veritas.com
PR_BODY_HTML before archive or after message has been restored:
Hi all,
What do you think?).

Managern
www.veritas.com
When using Outlook 2016 on the Enterprise Vault Server, the issue no longer exists.
There are three options to work around this issue.
1. Use Enterprise Vault Search to see emails in HTML format.
2. Upgrade Outlook from 2013 to 2016 on the Vault Server and remove Exchange 2010 from archiving.
3. Migrate users from Exchange 2010 to Exchange 2013/2016 and upgrade Outlook from 2013 to 2016 on the Enterprise Vault server.
Customers that are using Exchange 2010 in their Enterprise Vault environment have certain messages that open in text rather than HTML when using Vault Cache.