License Class Conflict Each Aspose component includes a License class. For more information, please check Use License. But Microsoft .NET Class Library has the same class name: System.ComponentModel.License . So in some situation, you will get License class naming conflict. To fix it, please specify the fully qualified name of the class when you use License.SetLicense method. Take Aspose.Words.License as an example: Aspose.Words.License license = new Aspose.Words.License(); The same thing could happen if you are using several Aspose products simultaneously and you have included using directives with appropriate namespaces, for example: using Aspose.Words; using Aspose.Pdf; The solution is the same - use fully qualified name for License class of each Aspose product.