#Migration Execution

Refer to the following sections to execute the migration.

#1. Configure projects and mappings in Fly

To configure projects and mappings, refer to the Create a Project and Create Migration Mappings sections in the User Guide for details.

#2. Perform regular full migrations

Before running the job, we recommend you verify the mappings to ensure that the mappings are available for migration. Refer to Pre-analyze Mappings for details.

Then you can run a full migration job to migrate the objects based on your configured migration policy. Refer to Run Migrations to Migrate Objects for details.

#3. Perform regular incremental migrations

Some issues may occur during a full migration job. Run an incremental migration job to handle new, updated, and failed data. Refer to Run Migrations to Migrate Objects about how to perform regular incremental migrations.

#4. Validate migration results

1. Check the mapping report. If the mapping fails or finishes with exceptions, you can check the error code and comment for the mapping in the Migration errors section. You can click the error code to view the details and recommendations of the code in the Troubleshooting Guide, which can assist you in resolving or avoiding the error.

   You can also view the migration summary of your projects within a specific time range in Report center.

2. Check the following data that are migrated to the destination tenant:

   • Chat messages and members

   • File attachment links in chat messages and OneDrive

   • HTML files that contain archived chat messages in OneDrive

   • New messages can be posted in destination chats.

   • Teams chat functions can work normally, such as posting messages, replying to messages, adding file attachments, and creating new chats.

#5. Perform the final cutover (optional)

After you change the domains of your Microsoft 365 tenants, the user principal names have been changed. Therefore, if you want to run the incremental migration job after the cutover, you need to use the Change mapping domain function in Fly to update the user principal names in migration mappings. Refer to the user guide for Change Mapping Domain for details.

#6. Perform the final incremental migration

Perform the final incremental migration job to ensure that all source data are migrated to the destination.

#7. Remove the service account (or the consent user) and placeholder account

You can delete the service account (or consent user of delegated app profile) and placeholder account from the destination Microsoft Entra ID after all migrations are finished. If you do not want to delete those users, you can use the Chat Migration Assist Tool to remove the service account (or consent user) and placeholder account from the destination chats. For details about how to use the Assist Tool, refer to Assist Tool for Microsoft Teams Chat Migration.

#8. Mark migrated messages as read

Messages migrated to destination chat users will be marked as unread by default. After all migrations are finished, destination chat users can manually mark the messages as read.