Suddenly my email router stopped working in my VPC. A look in the event viewer showed

#16192 - The E-mail Router service could not run the service main background thread. The E-mail Router service cannot continue and will now shut down. System.Configuration.ConfigurationErrorsException: The E-mail router service cannot access system state file Microsoft.Crm.Tools.EmailAgent.SystemState.xml. The file may be missing or may not be accessible. The E-mail Router service cannot continue and will now shut down. ---> System.Xml.XmlException: Root element is missing.
   at System.Xml.XmlTextReaderImpl.Throw(Exception e)
   at System.Xml.XmlTextReaderImpl.ThrowWithoutLineInfo(String res)
   at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
   at System.Xml.XmlTextReaderImpl.Read()
   at System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace)
   at System.Xml.XmlDocument.Load(XmlReader reader)
   at System.Xml.XmlDocument.Load(String filename)
   at Microsoft.Crm.Tools.Email.Providers.ConfigFileReader..ctor(String filePath, ServiceLogger serviceLogger)
   at Microsoft.Crm.Tools.Email.Providers.SystemState.Initialize(ServiceLogger serviceLogger)
   at Microsoft.Crm.Tools.Email.Providers.SystemState..ctor(ServiceLogger serviceLogger)
   at Microsoft.Crm.Tools.Email.Agent.ServiceCore.InitializeSystemConfiguration()
   --- End of inner exception stack trace ---
   at Microsoft.Crm.Tools.Email.Agent.ServiceCore.InitializeSystemConfiguration()
   at Microsoft.Crm.Tools.Email.Agent.ServiceCore.ExecuteService()

The file Microsoft.Crm.Tools.EmailAgent.SystemState.xml has been corrupted? Don’t know why or how it happened but I simple renamed my damaged file from the C:\Program Files\Microsoft CRM Email\Service folder (it's hidden) and started my Email router service. A new Microsoft.Crm.Tools.EmailAgent.SystemState.xml file is generated and populated with my <State> settings information.