Can DMA migrate and set a user account's Primary Group during a migration?
Does DMA migrate the Primary Group setting of a user account?
Domain Migration Administrator 7.x
Domain Migration Administrator will not migrate the Primary Group property of a user account. Domain Migration Administrator sets the primary group for migrated user accounts to Domain Users. If you use the Migrate associated user groups option and the source user account is assigned to a different primary group, Domain Migration Administrator migrates the primary group and assigns the user to this group in the target domain. However, the primary group of the migrated user is still set to Domain Users.
Domain Migration Administrator does not migrate the primary group in the source domain if the group is a built-in group.
For more information, see page 226 of the Domain Migration Administrator User Guide
For more information on how to use a script to make this modification, see the following article on Microsoft's Scripting Website:
Assign the Primary Group for a User