Two objects in directoy have same proxy - event 9514 after migration

[proudusa]

I migrated from exchange 5.5 to 2003. Some of the mailboxes resulted in duplicate accounts. Instead of user accounts it set them up as contact accounts with the same email addresses, etc. Now some internal e-mails are receiving an NDR because there are two accounts with same e-mail address. I tried changing the alias on the contact but that did not work.

Any ideas on why this would occur? i'm guessing it might have something to do with the recipient policy and auto creation of the e-mail but not sure how to resolve.
thanks

 

[proudusa]

It is actually safe to delete the contact accounts that were actually duplicates of existing user accounts. They both contained the same e-mail address and that resulted in the NDRs.

When deleting the accounts it tells you the associated mailbox will be deleted. The contact is deleted but no mailboxes are purged.