The Unified Modeling Language (UML) is a standard general-purpose modeling notation for object-oriented analysis and design of systems.
System Architect currently supports the following versions of UML, that are separate and distinct:
•UML 2.0 Lite which is based on the UML 2 metamodel. For details, see UML 2.0 Lite.
•UML 2.5 which provides a detailed implementation of the UML 2.5 specification.
It is strongly suggested you choose to use one or the other – not both. They are distinctly different metamodel implementations; turning both on would only serve to confuse you.