Exchange 2003 environment. Mid-migration to another Exchange 2003 org due to aquisition. Using Quest Migration Tools.(I don't think this is related to the migration tools, but just mention them to be complete).We're seeing NDRs for one internal recipient:Event Type: ErrorEvent Source: MSExchangeTransportEvent Category: NDR Event ID: 3029Date: 3/8/2010Time: 1:16:37 PMDescription:A non-delivery report with a status code of 5.1.4 was generated for recipient x-ex;/O=ABC/OU=XYZ/cn=Recipients/cn=Mickey.Mouse (Message-ID <6120BB823CEACA448B7ACB99B427F70F02D1DDE6@cab-ms-0001.abc.com>). [names changed to protect the innocent]Cause: Two objects have the same address as a proxy address and mail is sent to that address. Solution: Recheck the recipient address and ensure that two objects do not share the address. Attempt to resend the message. This can also be caused if the recipient does not exist at the remote server.Additional observations:A. When viewing the recipient in the Offline Address List in Outlook (2007), virtually all the fields are blank for this recipient, but the DISPLAY field (ie Display Name) contaings a LegacyExchangeDN.B. When I'm *not* in Cached Mode, and view the recipient in Outlook, he looks fine. (and recipient looks fine in ADUC and ADSIEDIT)C. When I use Message Tracking on one of the message that NDR, I see the recipients on the message listed like: 'displayname1; displayname2; /O=ABC/OU=XYZ/cn=Recipients/cn=Mickey.Mouse; displayname4'So my questions are:Q1: How do I find the other object with the duplicate proxy address? (I ran OABINTEG with PROXYTEST - but it didn't find anything)Q2: What can I do to fix his entry in the OAB? Can I remove clear out showInAddresBook and force RUS to 're-evalute' the object?Many thanks.

Q1: You could use LDP and do a query for the proxyAddresses attribute having smtp:user@company.com (or whatever it is). Q2: Remove the duplicate address in AD and the OAB will be fixed the next time it is scheduled to be generated.-- Ed Crowley MVP"There are seldom good technological solutions to behavioral problems.". "Drew-TX" wrote in message news:066c7d30-372f-481a-8b0b-e0544b2093a9... Exchange 2003 environment. Mid-migration to another Exchange 2003 org due to aquisition. Using Quest Migration Tools.(I don't think this is related to the migration tools, but just mention them to be complete).We're seeing NDRs for one internal recipient:Event Type: ErrorEvent Source: MSExchangeTransportEvent Category: NDR Event ID: 3029Date: 3/8/2010Time: 1:16:37 PMDescription:A non-delivery report with a status code of 5.1.4 was generated for recipient x-ex;/O=ABC/OU=XYZ/cn=Recipients/cn=Mickey.Mouse (Message-ID <6120BB823CEACA448B7ACB99B427F70F02D1DDE6@cab-ms-0001.abc.com>).. [names changed to protect the innocent]Cause: Two objects have the same address as a proxy address and mail is sent to that address. Solution: Recheck the recipient address and ensure that two objects do not share the address. Attempt to resend the message. This can also be caused if the recipient does not exist at the remote server.Additional observations:A. When viewing the recipient in the Offline Address List in Outlook (2007), virtually all the fields are blank for this recipient, but the DISPLAY field (ie Display Name) contaings a LegacyExchangeDN.B. When I'm *not* in Cached Mode, and view the recipient in Outlook, he looks fine. (and recipient looks fine in ADUC and ADSIEDIT)C. When I use Message Tracking on one of the message that NDR, I see the recipients on the message listed like: 'displayname1; displayname2; /O=ABC/OU=XYZ/cn=Recipients/cn=Mickey.Mouse; displayname4'So my questions are:Q1: How do I find the other object with the duplicate proxy address? (I ran OABINTEG with PROXYTEST - but it didn't find anything)Q2: What can I do to fix his entry in the OAB? Can I remove clear out showInAddresBook and force RUS to 're-evalute' the object?Many thanks. Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Hi,Please refer to the below article to find the duplicate proxy address:http://www.msexchange.org/articles/Finding-Duplicate-SMTP-Addresses.htmlFor the OAB issue, I suggest we first focus on the first issue and will handle it after resolving the duplicate proxy address.ThanksAllen

Thanks.Looks like the issue is a duplicate legacyExchangeDN.One of the objects was synched over from the aquiring company's forest (just to be visible in our GAL), and the other object was in our forest so that he could access our Voicemail system.Is it viable for me to modify the legacyExchangeDN on one of the objects?

Thanks.Looks like the issue is a duplicate legacyExchangeDN.One of the objects was synched over from the aquiring company's forest (just to be visible in our GAL), and the other object was in our forest so that he could access our Voicemail system.Is it viable for me to modify the legacyExchangeDN on one of the objects? Yes you can with one caveat that when other users will reply to the emails sent by this user, they might not be able to reply. In that case though they can send the replies by composing the new emails and then selecting the email address from address book. Just test it, and if you have problem then u can revert it back. Regards, Laeeq Qazi|Team Lead(Exchange + Sharepoint + BES + DynamicsCRM) www.HostingController.com

I modified one of the legacyExchangeDNs successfully (the one for the voicemail system since I figured that would have less impact).Everything is working fine now. No NDRs.Many thanks everybody.