When you delete an item from Deleted Items folder, there is a way to restore it from Personal Archive. Here is what you need to do:

  1. Login to My Services using your email address and mailbox password.
  2. Click Email Archiving > Manage Your Archive.

    My Services

  3. Click Filter and find the deleted message using any of the search criteria.
  4. The message can be recovered by either downloading a message in its original format (eml) or sending it back to your inbox as an attachment. Highlight the message you were looking for and select Send or Download accordingly.

Note: When exchange mailbox or the whole AD user is deleted, the data from the mailbox remains in the archive and can be accessed by a search admin.