Exchange 2010 + Outlook 2007. Users send outlook meeting request to a list of recipients both interanlly and externally to the organisation. Some recipients report receiving 'garbled' messages instead of meeting requests.
The emails received by some external recipients show emails with base-64 encoded attachments - and they are not able to add the meeting request to their calendar or even view it. Example of received email below:
Accept-Language: en-US, en-NZ Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US, en-NZ Content-Type: multipart/alternative; boundary="_000_A4701CF4E0917340AF3DD54B4BE141CA014EA83517WNS10compassh_" MIME-Version: 1.0 X-OriginalArrivalTime: 15 Jul 2011 03:15:21.0709 (UTC) FILETIME=[6E70D9D0:01CC429D] --_000_A4701CF4E0917340AF3DD54B4BE141CA014EA83517WNS10compassh_ Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 V2hl...yMNCg== --_000_A4701CF4E0917340AF3DD54B4BE141CA014EA83517WNS10compassh_ Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: base64 PGh0b...bWw+DQo= --_000_A4701CF4E0917340AF3DD54B4BE141CA014EA83517WNS10compassh_ Content-Type: text/calendar; charset="utf-8"; method=REQUEST Content-Transfer-Encoding: base64 QkVHS...jIyMjIyMNCg== --_000_A4701CF4E0917340AF3DD54B4BE141CA014EA83517WNS10compassh_--
I've shortened the base 64 encoding blocks in the above sample, but I can confirm that I've manully re-encoded the base 64 and they convert appropriately to a plain text version of the request, an HTMl version, and an .ics file which opens fine in outlook (2010).
These particular recipients normally get meeting requests fine, but something seems to be causing a probles with some of these requests.
The external recipients report using 'Outlook', but at this stage we can't be sure if it is Outlook, or Outlook Express or which specific versions.
Searching google, some bug reports for Thunderbird describe the client not re-encoding attachments, but none of our recipients seem to be using Thunderbird. There also appears to be some discussion about Outlook 2000 not opening .ics files - however , the recipients can't even see the attachments as such - but rather just encoded base 64 MIME.