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Its a possibility when you reimported the mail items into the mailbox, it striped out attributes from that message. I would look using MFCMAPI at one of the messages and see if the PR_SENDER_ADDRESS is valid on the message that is giving the NDR.
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I read that, very good by the way. So if there is a contact created anywhere in exchange it will cause this? Even a users contact?
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Correct. Outlook will resolve the SMTP address to the contact object.<br />
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-JJ
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I had a senior moment DOH! The test I ran I did a reply to all, and there was an exchange object in the cc. Ooops. The external address worked fine, it was the exchange object generating the NDR. &nbsp; Thanks!
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We had an EDB from another organization that we needed some messages from. I used a 3rd party tool Lepide Exchange Recovery Manager to export the messages to a pst and then imported them to the Exchange 2010 mailbox.<br />
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The messages are there and look fine, but when replying to one it throws the above error. After searching I've found a lot of posts regarding X500 and LegacyExchangeDN, but the kicker here is that this is being replied to an external user NOT internal so that shouldn't be an issue. It does this from OWA and Outlook so it isn't an autocomplete issue either.<br />
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Thoughts?
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We had an EDB from another organization that we needed some messages from. I used a 3rd party tool Lepide Exchange Recovery Manager to export the messages to a pst and then imported them to the Exchange 2010 mailbox.

The messages are there and look fine, but when replying to one it throws the above error. After searching I've found a lot of posts regarding X500 and LegacyExchangeDN, but the kicker here is that this is being replied to an external user NOT internal so that shouldn't be an issue. It does this from OWA and Outlook so it isn't an autocomplete issue either.

Thoughts?

#550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found # Error when replying to imported PST messages

Exchange is the server side of a collaborative application product that is part of the Microsoft Server infrastructure. Exchange's major features include email, calendaring, contacts and tasks, support for mobile and web-based access to information, and support for data storage.