PowerDesigner provides default model checks to verify the validity of messages.
| 
                             Check  | 
                        
                             Description and Correction  | 
                    
|---|---|
| 
                             Message without sequence number  | 
                        
                             A message should have a sequence number. Manual correction: Enter a sequence number on the message Automatic correction: None  | 
                    
| 
                             Message used by several instance links  | 
                        
                             A message should not be attached to several instance links. Manual correction: Detach the message from the instance link Automatic correction: None  | 
                    
| 
                             Message between actors  | 
                        
                             An actor cannot send a message to another actor in the model. Messages are allowed between two objects, and between objects and actors. Manual correction: Create a message between two objects or between and actor and an object Automatic correction: None  |