Dmitry, I have a similar problem:

We've written an application that processes e-mails we receive in Outlook
and computes their MD5 hash values. So far it works alright for all file
types, except attached .msg files (note we are not saving a certain message
in the .msg format, but rather saving an attached .msg file).
To our surprise, MD5 hashes vary for attached .msg files (and only for
these). I mean, if I save an attached MSG twice, first as 1.msg and then as
2.msg, their hash values differ. Why's that? I assumed Outlook handled
attached .msgs as if they were any other file type, but now it seems not
(other file types get identical hash values when saved twice).
Any clues?

"Dmitry Streblechenko" wrote:

Entry id is never stored in the MSG files since it only makes sense in the
context of the parent store, which MSG files do not have.
Which message id do you mean? The one from the MIME headers? Note that some
messages (e.g. the ones stored in the Sent Items of a PST store) do not even
have a MIME headers.

Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool

"peketi" wrote in message
...
Thanks for the information. Initially I thought it may be the 'Entry ID'
which is the only thing different but you have given me some more insight
to
this problem. Is there a way out to get the 'Message-ID' from the
message,
may be that would help me solve this problem. Your help is this regard
would
be highly appreciated.


"Dmitry Streblechenko" wrote:

Some properties can and will be different, e.g. PR_SEARCH_KEY. Most
likely
neither you nor your users care about these properties, but they will be
make the MSG fiel different.
Secondly, the order in which properties are streamed to the MSG file can
be
different, so even if the mesasge is the same, the hash will be
different.
You need to use a different algorithm to determine whether two messages
are
the same, such as comparing the message body, subject, recipients, etc.

Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool

"peketi" wrote in message
news I am writing an application that generates a message digest (MD5) for a
MSG
file generated by Outlook application. If I generate a MSG file each
from
2
PST files, FILEA.PST and COPY_OF_FILEA.PST (* COPY_OF_FILEA.PST is a
copy
of
FILEA.PST *), A.MSG and A1.MSG, I get a hashvalue or the message digest
different for these messages though the content of these messages are
same.
Any reasons for this and workarounds ?