Duplicates in the Archive?

Why are there duplication in the archive following a Legacy Data Import?

Scenario: 

Browsing/Searching In MyArchive: You need to search for an Email from the legacy import. You locate the Email but see many duplicates of the same message. You know that you only received this message once in Outlook.

Reason For "Duplicates": If a message is sent to multiple users on the same mail store. Exchange will keep one copy of the message and allow access to this message to multiple mailboxes on the same store (Single Instance Storage).  However, when a mailbox is exported a copy of every message that individual should have in their mailbox is stored to the external location (folder for .EML or PST, MBOX etc). If performing the same role for multiple users, the same message will be exported for each mailbox export request, and each individual will have their own copy of all their emails (sent and received) including those that were sent to multiple individuals.

How the duplication got into your archive: You have a need to have a copy of all your legacy email added to the archive.  You will export the data from your current mail server/service, quite likely using a similar approach from the above paragraph.

When the data supplied is ingested to the archive account, our indexing process will not eliminate any duplicates and will ingest all copies of the message to retain data integrity. 

When the data is displayed in search results, our back-end systems will display all messages that contain the users SMTP address, and since there are multiple copies of the message (from the other import sets) that contain your email address as a recipient or sender, the service takes these into account and places a tag to be shown in your own view, therefore multiple messages of the same will be displayed.

Can I delete these duplicates?
No, there is no feature that is automated to detect duplication.