The Business Units concept is at the core of security model in Microsoft Dynamics CRM. As such, all users will be part of a Business Unit. The structure includes a default Business Unit, created when an Organization is created. From there, child Business Units can be created as needed, resulting in a tree structure as complex as designed. The following screenshot shows a parent Business Unit, with two child ones (IT and Finance), and IT has another three child Business Units (Cloud, Delivery and Infrastructure):
The Root Business Unit is the top-most Business Unit, and it is the one created with the Organization by default. As a rule, there always is a Business Unit in an Organization, and that is the Root Business Unit. This Business Unit cannot be removed or disabled, and is the container that allows transferring security settings with solution packages from one organization to another.
The ribbon depicted in the above screenshot has the necessary commands to...