Symptoms
Assume that you run the Start-MigrationUser cmdlet to manually start a user migration after a public folder batch migration fails. In this situation, you receive an error message that resembles the following message:
The migration user test6@exhv-2598dom.extest.microsoft.com can't be found.
+ CategoryInfo : NotSpecified: (:) [Start-MigrationUser], ManagementObjectNotFoundException
+ FullyQualifiedErrorId : [Server=EXHV-2598,RequestId=f6f829d8-bb9c-40bb-ab3f-1ccad2f15bec,TimeStamp=2/7/2022 11:07:26 PM] [FailureCategory=Cmdlet-ManagementObjectNotFoundException] D8FE0F69,Microsoft.Exchange.Management.Migration.
MigrationService.User.StartMigrationUser
+ PSComputerName : exhv-2598.exhv-2598dom.extest.microsoft.com
This error occurs if the migration batch is in a stopped state. In this situation, you have to wait for more than three mins for the batch to sync before you can start a specific user migration.
Resolution
To fix this issue, install the following updates, as appropriate: