Answer :
- Run the New-MailboxSearch cmdlet
- Run the Set-IRMConfiguration cmdlet
- Export the results from the discovery mailbox to a personal folders (PST) file, and then use Microsoft Outlook to open the PST file.
Explanation :
https://technet.microsoft.com/en-us/library/dn440164(v=exchg.160).aspx?f=255& MSPPError=-2147217396 https://technet.microsoft.com/en-us/library/dd353189(v=exchg.160).aspx