Exchange Cutover Migration - Sync Errors

Question

I just started a new Migration Batch where a few mailboxes failed because of below:

The proxy address "SMTP:*** Email address is removed for privacy ***." is already being used by the proxy addresses or LegacyExchangeDN. Please choose another proxy address.

I have run commands with onprem Exchange Server to find any object containing this email address but only the mailbox objects were returned. How can I resolve this? Do I need to do anything before trying a 'Resume' in Migration Batch. Ideally I don't want to use PST migration so looking for a solution - in addition these mailboxes are members of some groups that consequently failed due to the fact the mailboxes failed.

Run Get-Recipient | where {$_.EmailAddresses -match "*** Email address is removed for privacy ***"} | fL 
Name, RecipientType,emailaddresses

I see this https://community.office365.com/en-us/f/156/t/288722 but not sure if this is what I should do.

Mailbox is not created but User is in O365.

Answer 1

OK, so just to be sure, if I delete the existing Migration Batch, then create a new Migration Batch the new one will perform initial sync on all mail items (Contacts, Groups, Mailboxes) it finds, not sync data already in cloud, perform 24 hour syncs. I just want to make sure that the mailboxes which have been successful will continue to sync every 24 hours.

Can you confirm the above AND provide any other advice on how to action?

Answer 2

I ran all three against EO and returned zero results. What is the best course of action from here? Would deleting the current MB then creating a new one be the best thing? Are there any issues with doing this?

Answer 3

Hi David,

Thanks for your information.

In a Cutover migration, there is only one migration batch can be added. If you create a new migration batch for all users, it won't re-sync all data previously uploaded to Office 365. It will only sync the new mailboxes and do delta sync every 24 hours after completing the initial sync. Before doing that, given the situation, please try using the following PowerShell commands to check it through Exchange online PowerShell:

Get-Mailbox | Where {$_.EmailAddresses -match "*** Email address is removed for privacy ***"} | select Identity, DisplayName, RecipientType

Get-MailUser | Where {$_.EmailAddresses -match "*** Email address is removed for privacy ***"} | select Identity, DisplayName, RecipientType

Get-MailContact | Where {$_.EmailAddresses -match "*** Email address is removed for privacy ***"} | select Identity, DisplayName, RecipientType

Please let me know whether there is any result.

Best Regards,

Erick

Answer 4

You may of seen I replied above (was logged in as another customer at the time). I also tried a few commands with onsite Exchange/AD and still no luck :(

proxyaddresses=smtp:*** Email address is removed for privacy *** with AD LDAP Find (www.msexchange.org/.../Finding-Duplicate-SMTP-Addresses.html)

Also used a free tool using the same type of search (www.joeware.net/.../index.htm)

Would it be worth deleting the current Migration Batch then adding a new one? I am assuming that this would not affect existing data already in the cloud?

Answer 5

Thanks Erick.

No results on Exchange Online

One result on InHouse Exchange (Users mailbox)

Same for both mailboxes that failed.