- You don't receive all your email.
- When someone tries to send mail to you (the newly migrated user), they receive a non-delivery report (NDR).
- Initial writeback process
Some directory information (for example, msExchMailboxGuid and publicDelegates) must be transferred from the Dedicated directory to Azure Active Directory. To do this, the required information is extracted from the Dedicated directory and written to your on-premises Active Directory. From there, AAD Sync/Connect is used to transfer the information up to the cloud. This writeback performed manually and coordinated with Microsoft deployment resources in advance of migrations.
- License object in vNext and provide the batched users to the EXO team (Customer)
As soon as the writeback process is completed, the customer will take steps to batch and license the objects by running the script provided by the EXO service team in the configuration documentation. Because the msExchMailboxGuid element is copied from legacy dedicated to the on-premises AD to vNext, this prevents a new mailbox from being provisioned and makes sure that the move is completed successfully.
Note If the license is added before step 1 occurs or step 1 isn’t completed successfully, a new mailbox will be provisioned and have to be manually cleaned up. See KB 3202607 Mailbox is present in both Office 365 Legacy Dedicated and vNext after license is applied for more information.
- Freezing of mailboxes
Before the moves are submitted, the mailboxes are frozen. Therefore, the targetAddress and proxyAddresses properties are no longer updated by MMSSPP. After the move, the source mailbox will be configured by the Mailbox Replication Service (MRS) to make sure mail delivery continues. These attributes should remain permanently frozen after the migration to avoid any changes.
- Pre-seeding (MRS)
A group of mailboxes will be included in a migration batch that's provided by the customer to the Microsoft deployment resource. This must be completed several weeks before the mailbox is migrated so that the new mailbox can be pre-seeded in vNext.
- Final migration (MRS)
The mailbox move is completed on the date and time requested by the customer.
- Final writeback
Within three business days, a final writeback will be completed. The properties updated are targetAddress, msExchRecipientTypeDetails, msExchRemoteRecipientType, msExchRecipientDisplayType, and proxyAddresses.
- Non-delivery reports (NDRs), if available
Review the configuration of the object in the legacy dedicated environment. The object should be a RemoteUserMailbox with an ExternalEmailAddress attribute and a suffix of *.onmicrosoft.com:
get-recipient firstname.lastname@example.org | fl ExternalEmailAddress,RecipientTypeDetails
ExternalEmailAddress : SMTP:email@example.comRecipientTypeDetails : RemoteUserMailbox
ExternalEmailAddress should be an email address on the vNext mailbox.
If there are concerns that the source object in legacy dedicated is configured incorrectly, please engage Microsoft for additional investigation.
*There is a project underway to automate the writeback process. As soon as the automation is put in place, writebacks will occur continuously, and additional steps will be unnecessary.
Article ID: 3189107 - Last Review: May 4, 2017 - Revision: 4