Corrupt summary TNEF content - Error 5.6.0

Question

Hi,
We are on Exchange 2013 CU3, and users are unable to send email when a message .msg file is used to create the email via outlook.
The error message when sent to external (outside our exchange server realm) is :
Diagnostic code = ContentTypeUnsupported; Reason code = TransferFailed; Status code = 560
< #5.6.0 smtp;550 5.6.0 M2MCVT.StorageError; storage error in content conversion
Error when sending to internal users on exchange.
Remote Server returned '554 5.6.0 Corrupt message content; STOREDRV.Deliver.Exception:ConversionFailedException; Failed to process message due to a permanent exception with message
Content conversion: Corrupt summary TNEF content. ConversionFailedException: Content conversion: Corrupt summary TNEF content. [Stage: CreateReplay]'
I looked on this forum itself and these errors existed it seems prior to 2013 as well, looks like its back in 2013 ? Would the CU 5 update deal with these issues because i almost think that upgrading to CU5 should resolve it unless
there is some connector issues where we are dealing with.
Thanks

Answer 1

Wanted to mention that this behavior can be rectified when we turn off the "Confidentiality Notice".  Seems like an issue when trying to attach that Confidentiality notice at the end of the emails.
The Notice is basically the rule stating Append with Disclaimer at the bottom of all email sent from inside the organization.