If the item is of the '.msg' file type, Outlook will preview the item. When a PST file is connected to and opened in Microsoft Outlook, the listing of the PST file contents appears and the first item is attempted to be previewed in the Preview pane if the preview feature is enabled. A CA or DA export of those items exports them as '.eml' files which can be hoovered up into Outlook PST files using the proper versions of Microsoft Outlook installed on the CA or DA server. When the EV 11.0.1 or greater SMTP Archiving feature archives those items, they are saved in the EV Vault Store Partition as '.DVS' type files. The content of those '.eml' files is the P1 envelope containing author and recipient information as well as an attachment that is the original message in '.msg' file format. SMTP messages are presented to the EV (Enterprise Vault) SMTP Holding Folder are in the form of '.eml' files. This file cannot be previewed because there is no previewer installed for it.

Items archived via EV SMTP and exported by Compliance Accelerator (CA) or Discovery Accelerator (DA) into PST files cannot be previewed in Outlook.