To use the Exchange Management Console to configure deleted item retention for a mailbox database
1. Open the Exchange Management Console.
2. In the console tree, expand Microsoft Exchange, then expand Server Configuration, and then select Mailbox.
3. On the Database Management tab in the work pane, expand the storage group that contains the mailbox database that you want to configure.
4. Right-click the database that you want to configure, and then select Properties.
5. Click the Limits tab.
6. In the Deletion settings area, enter the number of days to retain deleted items in Keep deleted item for (days).
7. Click OK to save the changes.