Search mail in all mailboxes in Exchange 2010:
Add user to exchange group - Discovery Management (members of this group can perfomr search of mailboxes in the Exchange organization)
Enable this user Manage Full Access Permitions to mailbox Discovery Search Mailbox (you will see search result in this mailbox)
Open ECP (Exchange Control Panel) from brouser and log on.
Open Reporting.
Add user to exchange group - Discovery Management (members of this group can perfomr search of mailboxes in the Exchange organization)
Enable this user Manage Full Access Permitions to mailbox Discovery Search Mailbox (you will see search result in this mailbox)
Open ECP (Exchange Control Panel) from brouser and log on.
Open Reporting.