Microsoft Exchange Transport Service wont start

Hi

I have an issue that has turned up randomly and not sure where the issue comes from.
This server has been operational with no issues for over 12 Months.

This morning I cannot send or recieve email from the server.

Microsft exchange transport service will not start and I have some odd permission errors happening.
I have made sure that NETWORK SERVICE has full access to C:\Program Files\Microsoft\Exchange Server\V14 but I have a tick in the read only attribute for all these folders. The tick is greyed out but I can remove it and it goes and applies it to all the subfolders and files but when I go back and check the attributes again the tick has returned. Is this my issue?

Below is the error as viewed in the event log.

Any assistance in finding the fault here would be much appreciated.

Cheers
Paul

Microsoft Exchange couldn't start transport agents. The Microsoft Exchange Transport service will be stopped. Exception details: Failed to create type 'Microsoft.Exchange.Transport.Agent.ContentFilter.ContentFilterAgentFactory'from assembly 'C:\Program Files\Microsoft\Exchange Server\V14\TransportRoles\agents\Hygiene\Microsoft.Exchange.Transport.Agent.Hygiene.dll' due to error 'Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))'. : Microsoft.Exchange.Data.ExchangeConfigurationException: Failed to create type 'Microsoft.Exchange.Transport.Agent.ContentFilter.ContentFilterAgentFactory'from assembly 'C:\Program Files\Microsoft\Exchange Server\V14\TransportRoles\agents\Hygiene\Microsoft.Exchange.Transport.Agent.Hygiene.dll' due to error 'Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))'. ---> Microsoft.Exchange.Data.ExchangeConfigurationException: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED)) ---> System.UnauthorizedAccessException: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))
   at Microsoft.Exchange.Data.Transport.Interop.UnsafeNativeMethods.CoCreateInstance(Guid rclsid, Object pUnkOuter, UInt32 dwClsContext, Guid riid)
   at Microsoft.Exchange.Data.Transport.Interop.ComProxy..ctor(Guid guidClass)
   at Microsoft.Exchange.Transport.Agent.ContentFilter.ContentFilterAgentFactory.InitializeFilter()
   --- End of inner exception stack trace ---
   at Microsoft.Exchange.Transport.Agent.ContentFilter.ContentFilterAgentFactory.InitializeFilter()
   at Microsoft.Exchange.Transport.Agent.ContentFilter.ContentFilterAgentFactory.Configure(Boolean onStartup)
   at Microsoft.Exchange.Transport.Agent.ContentFilter.ContentFilterAgentFactory..ctor()
   --- End of inner exception stack trace ---
   at Microsoft.Exchange.Data.Transport.Internal.MExRuntime.FactoryTable.CreateAgentFactory(AgentInfo agentInfo)
   at Microsoft.Exchange.Data.Transport.Internal.MExRuntime.FactoryTable..ctor(IEnumerable agents)
   at Microsoft.Exchange.Data.Transport.Internal.MExRuntime.RuntimeSettings..ctor(MExConfiguration config, String agentGroup)
   at Microsoft.Exchange.Data.Transport.Internal.MExRuntime.MExRuntime.Initialize(String configFile, String agentGroup, Boolean isBridgeHead, String installPath)
   at Microsoft.Exchange.Transport.Extensibility.AgentComponent.Load()