Validating UML models and diagrams

At any time during the construction of a UML model or diagram, you can check that it complies with the defined constraints and ensure that no broken cross-model references exist.

Before you begin

You must have a model open in the Modeling perspective and you must enable at least one constraint category in the Validation preferences.

About this task

There are three levels of model validation severity:

  • An error is a critical violation that is not allowed.
  • A warning is less severe than an error and indicates a rule violation that is allowed, but that results in your model being semantically incorrect.
  • An informational message is the least severe form of violation and indicates a rule that is inconsistent with UML standards but that does not need to be corrected.


  1. To validate a model, diagram, or model element, right-click the item; then click Validate. Any violations are listed in the Problems view.
  2. To view the subject of a validation error or warning, in the Problems view, right-click an error or warning; then click Go To. The involved model elements are selected in the Project Explorer view. The list of validation errors is also displayed in the Alerts and Action Items section of the UML Model Editor.