Inline UUEncoded attachments of email messages from a UNIX-based application are garbled or are unreadable

Original KB number:   2590107


Consider the following scenario:

  • A user receives an email message from a UNIX-based application.
  • The email message contains an inline UUEncoded attachment.

In this scenario, the attachment is garbled or is unreadable. Additionally, the attachment is displayed as the following picture in the email message body:

Screenshot of the email message body.

Note: The following content is displayed in an affected message header.

MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"


This issue occurs because of "begin 664." It indicates that UUEncoding is being used. When an email message contains an inline UUEncoded attachment, multipart MIME instead of MIME should be used. Otherwise, Microsoft Exchange translates the UUEncoded data as a part of the message body that has a MIME designator.


To resolve this issue, encode the message by using multipart MIME.

Note: The issue cannot be resolved on an Exchange server because Exchange displays the messages according to the specified MIME encoding type.

More information

For more information about MIME, visit the following website:

General information about MIME

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