"ConversionFailedException" error when emails are sent on the hour in Exchange Server 2013

Applies to: Exchange Server 2013 EnterpriseExchange Server 2013 Standard Edition

Symptoms


In a Microsoft Exchange Server 2013 environment, when emails are sent to large distribution groups on the hour (for example, 1:00, 2:00, 3:00 ... 12:00, 13:00, etc.), the delivery fails for some recipients. Additionally, you receive an error message that resembles the following:
{LRT=};{LED=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]};{FQDN=};{IP=}]

Resolution


To fix this issue, install Cumulative Update 15 for Exchange Server 2013 or a later cumulative update for Exchange Server 2013.

Status


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

References


Learn about the terminology that Microsoft uses to describe software updates.