Error al crear diagrama de base de datos sql server

El error es:

Database diagram support objects cannot be installed because this database does not have a valid owner. To continue, first use the Files page of the Database Properties dialog box or the ALTER AUTHORIZATION statement to set the database owner to a valid login, then add the database diagram support objects.

Y la solucíón:

ALTER AUTHORIZATION ON DATABASE::YourDatabaseName TO sa

Sean felices! :) Y siéntanse libres de opinar ;)