Migrate from multiple sources to one user account


You want to know if you can perform multiple data migration processes for a single target account.


  • Admin console


Note: As explained in the article it's highly recommended to perform this action individually.

Can I migrate from multiple sources to one user account?

Not at the same time. The data migration service won't migrate from multiple source accounts to a single target account. Migrating data to the same target account when a migration is already running doesn't add additional data to the target account. It cancels the first migration.

If you want to migrate from multiple source accounts, let the first migration complete before beginning a second migration. The second migration removes the other (completed) migration from the list of active migrations, but this won't affect any active migrations or mappings.

Example—Migrating user accounts

  • You're migrating data from source-user1 to target-user1. Then, you add another migration from source-user2 to target-user1. Target-user1 ends up with data from source-user2 and only partial data from source-user1 (rather than data from both source accounts). The second migration cancels the first migration.

Examples—Migrating calendar data

  • You set up an identity mapping CSV file where multiple source identities are mapped to a single target identity. After a migration, only one of the mappings applies and the others are discarded. There are no errors or warnings that this occurred.
  • You set up an identity mapping CSV file and map source-identity1 to target-identity1. Then, when you are setting up your migration, you click Add user and map source-identity2 to target-identity1. During a migration, source-identity2 is mapped to target-identity1 and the identity mapping is discarded without errors or warnings.

    If source-identity1 is a user, events that have source-identity1 as an attendee or organizer don't transfer to the target user. The target user instead becomes the organizer or attendee of events that has source-identity2 as the organizer or attendee.


You performed several data migrations to a single target account but you can only see one process, the others are gone.