When using Thunderbird to send a .doc attachment the e-mail message is rejected by Exchange 2007 with the response: ” #554 5.6.0 STOREDRV.Deliver; Corrupt message content
##rfc822;”.

In some instances the Thunderbird mail client may send a .doc file (Word attachment) with the incorrect mime-encoding of ‘application/applefile’.
See also: Thunderbird normally sends attachments inline (as part of the message body), not as real attachments.

Perform the following steps to resolve the problem:

  1. Close Thunderbird.
  2. Navigate to the following directory based upon your OS:
    • Windows 2000/XP: %userprofile%\Application Data\Thunderbird\Profiles
    • Windows Vista: %userprofile%\AppData\Roaming\Thunderbird\Profiles
    • Mac OS X: \Library\Thunderbird\Profile
  3. Open the directory named with a random set of characters like ”yo6luyl8.default”. There may be multiple directories if you have multiple Thunderbird profiles.
  4. Delete the file named ‘mimeTypes.rdf’.