After all the objects have been successfully migrated to the target environment, the directory synchronization job can be stopped and the Directory Synchronization Agent uninstalled.
Once you are sure that the migration was indeed carried out smoothly, that access to resources has been preserved, and that your help desk is not experiencing a sharp increase in the number of calls, it is good practice at this stage to disable the source accounts and thus make sure that all users are logging on with their target accounts.
We recommend that you wait some time after disabling the source accounts to make sure that all users are using their target accounts before beginning cleanup.
To clean up the service attributes used by the Directory Synchronization Agent during migration and synchronization, you can use the Active Directory Cleanup Utility for Migration Manager. The utility is available in the Migration Manager for Active Directory Resource Kit.
Caution: The Directory Synchronization Agent adds to the proxy address list of each synchronized target user an x500 address that is equal to the legacyExchangeDN attribute of the matching source user. Do not delete these x500 addresses unless you are certain they are no longer needed. The x500 addresses are used for the following purposes:
If you delete these x500 addresses from the proxy address list of the target mailbox later, the OST file associated with the mailbox will become inaccessible and other users will no longer be able to reply to old e-mail sent by users whose addresses have been deleted.
Therefore, you should never delete auxiliary x500 addresses added by the Directory Synchronization Agent unless you are absolutely sure that the ability to reply to the old e-mails is no longer needed and you want to rebuild the OST files.
After the distributed resources and BackOffice servers have been processed, we recommend you wait some time to ensure that everything is working right before cleaning up SIDHistory attributes from the target user accounts.
SIDHistory cleanup is done by the Active Directory Processing Wizard. Choose the Cleanup objects SIDHistory option for Active Directory processing. Refer to the Active Directory Processing section of Migration Manager for Active Directory Resource Processing Guide for more details.
If after SIDHistory cleanup some users cannot access resources, SIDHistory can be re-applied back to the accounts that lost access only by re-migrating these accounts (with the merge option). This will give you time to check whether the resources were processed correctly for these accounts, fix the problem, and clean up SIDHistory again.
After SIDHistory is cleaned up, wait some time to ensure that all target users can access the resources they used before the migration.