'Service failed on execute: System Error. The parameter is incorrect.' The service is not accessing network resources and not connecting to exchange servers. It does not interact with the desktop and runs using the local system account. In the properties of the service the serviceStartName is the domain username (where the username is the administrator), whilst the password is the administrators password. It may be that this is the cause of the problem but I do not know why the error is not being raised each time the service is executed.