Does Domain Migration Administrator delete the source account during a migration?
Domain Migration Administrator 6.x
Domain Migration Administrator 7.x
DMA does not delete the source account as the source account is migrated. If there is a problem in the target domain, then the source domain will still be available. This applies to users, groups, and computer accounts. You may be able to delete the source account through scripting but it is not suggested. As an alternative you can disable source user account during an account migration by selecting this option in the Migrate User Accounts wizard or in the Specify Migration Settings wizard.
When migrating accounts between a Windows NT 4 domain and Active directory, or between two different forests, DMA is performs a copy. DMA only performs a move when source and target domains are in same forest and target domain is in native mode.