A.From the Exchange Management Shell, run Set-MailboxDatabase -DumpsterStatistics $true.
B.From the properties of the mailbox database, select the This database can be overwritten by a restore check box.
C.From the Exchange Management Shell, run the New-MailboxSearch cmdlet.
D.From the Exchange Management Shell, run the New-MailboxExportRequest cmdlet.
E.From the properties of the mailbox, enable single item recovery.
F.From the properties of the mailbox database, modify the Deletion Settings.