You can stop an action from running by editing the code.
Within an action, you may come across a situation where you don't want the action to run. For example, you may be using a Copy action, but after filtering the file list, there isn't anything left to copy. If that happens, you can just leave one or more of the critical rule parameters blank to cause the rule to fail or you can throw an exception. Either way, an error appears in the History log. If an exception is generated, the exception message is also displayed in the History log. The action.Error event is still raised.

' Give up on this action and throw an exception
Throw New ApplicationException("Missing file.")