Error unpacking TNEF (Winmail.dat)


This article applies to:

  • MailMarshal Exchange 5.3.X
  • Exchange 2007 

Symptoms:

  • Error: "Invalid TNEF file – winmail.dat>"

    Unpacking TNEF file.
    Failed to load tnef objects. ReadExact: read only 1 bytes requested 4
    TNEF file unpacking *FAILED*.
    Event - Unpack for BA001387DD.0013A681.mml caught exception <Invalid TNEF file - winmail.dat>


  • Affected messages are deadlettered by MailMarshal Exchange

Possible Cause:

  • This error can occur when differing versions of Exchange 2007 are used within the same domain (for example Exchange 2007 SP1 Roll-up 6 and Exchange 2007 Roll-up 7).
  • The winmail.dat file is actually corrupt - this is not a MailMarshal Exchange fault.

Possible Workarounds:

  • It may be possible to resolve the problem by ensuring all Exchange 2007 instances within the domain/organization are on the same service pack level.
  • With previous TNEF compatibility issues, Microsoft has recommended not using Word as email editor.

Notes:

There are other possible causes of TNEF unpacking errors. This error is specific to the environment named.


Last Modified 7/29/2009.
https://support.trustwave.com/kb/KnowledgebaseArticle12904.aspx