Active Directory Object Contains Other Objects. Are you sure you want to delete object and all of the objects it contains?
If you attempt to delete a user from Active Directory, you may receive a warning about other content objects.
This is most likely due to Exchange 2010 attributes. To delete the user safely, proceed by viewing the objects contained in this way:
now expand the branch of the user you need to delete, here you can see some old information about the active sync device left by an old Exchange server installation.
delete child objects (SAMSUNG ..) and the ExchangeActiveSyncDevice folder.
Now you can safely delete the user.