Client Access Licenses (CALs) are required by Microsoft for users or devices to access Microsoft server services like file storage or printing. There are two main types of CALs - User CALs which are purchased for each individual user accessing services, and Device CALs which are purchased for each device accessing services regardless of the number of users. Remote Desktop Services CALs are also available for allowing remote desktop access. User profiles in Active Directory can be Normal, Roaming, or Mandatory depending on whether user settings are saved locally, roam between devices, or cannot be changed.