Migration from 2007 and Archive Mailbox PST import question

Question

Our enterprise will be migrating from Exchange 2007 SP3 to Exchange 2013 CU3 very shortly. Exchange 2013 is set up and I am in coexistance mode currently. Everything is working fine with the legacy redirection, I have tested some mailbox migrations and they
work fine. We currently use Mimosa Nearpoint as a third party email archive product.
As part of this migration from 2007 to 2013, we plan on moving away from Mimosa Nearpoint and utilizing the Exchange 2013 Archive Mailbox feature. We will give each user an Archive Mailbox. We have the ability to export the users existing archive out of
NearPoint to .PST files and then migrating them directly into the users Archive Mailbox using the "New-MailboxImportRequest -IsArchive" powershell commandlet. This has been tested and works fine with one very important exception.
When I export from Nearpoint, I have to export the entire contents of the archive, I cannot set date ranges. So when I do an export, it also contains the contents of the user's mailbox. I have managed folder policies in place in the Exchange 2007 environment
which delete all contents of the mailbox older than 60 days, but when I import the .PST to the archive, it imports ALL items into the Archive Mailbox. So I have 60 days worth duplication of items.
It is my understanding that if I imported the Archive .PST directly into the users production mailbox in the 2013 side, that it would not import duplicate items. I am trying to find out if there is any process which will do the same thing with me importing
directly into the users Archive Mailbox.
Thanks you,

Answer 1

Hi,
We used a third patry email archive product to export to .pst files, so it is too hard to say that whether it cause this issue.
However, I found a method to delete the duplicate items from our mailbox via MFCMAPI Tool.
Please make sure that the Exchange Server mailbox has been backed up first.
Details in the following KB:
How to remove duplicate folders in Outlook when connected to an Exchange Server mailbox
http://support.microsoft.com/kb/2509983
I also found a script to remove duplicate items.
This script will scan each folder of a given mailbox and removes duplicate items from those folders. You can specify how the items should be deleted and what items to process, e.g. mail items or appointments. Sample usage is after a misbehaving synchronization
tool creates duplicate items or (accidental) import of PST file with duplicate items.
*****Please also make a full back up first*****
Removing Duplicate Items from a Mailbox
http://gallery.technet.microsoft.com/office/Removing-Duplicate-Items-f706e1cc#content
Disclaimer       
The sample scripts are not supported under any Microsoft standard support program or service.
The sample scripts are provided AS IS without warranty of any kind. Microsoft further disclaims all implied warranties including, without limitation, any implied warranties of merchantability or of fitness for a particular purpose.
The entire risk arising out of the use or performance of the sample scripts and documentation remains with you.
In no event shall Microsoft, its authors, or anyone else involved in the creation, production, or delivery of the scripts be liable for any damages whatsoever (including, without limitation, damages for loss of business profits, business interruption, loss
of business information, or other pecuniary loss) arising out of the use of or inability to use the sample scripts or documentation, even if Microsoft has been advised of the possibility of such damages.
Hope it is helpful
Thanks
Mavis
Mavis Huang
TechNet Community Support