Outlook automatically sending "Not read" receipts

[Guest]

My "Outlook Send/Receive Progress" window frequently reports messages being
sent even though I have not sent messages and nothing new appears in either
my Outbox or Sent Items box. Other posts on this forum claim that these
messages are most likely read receipts. I have confirmed that these messages
are stored in .pst files. I have a .pst file saved that contains 44 of these
messages. When the messages are sent, many are rejected with a "User unknown"
message, or something similar, returned to me. By looking at these returned
messages it appears that most (if not all) of the messages that my Outlook is
automatically sending have a subject that begins "Not read".

I have seen several posts relating to this or similar problems, but have not
seen satisfactory answers to a couple critical questions:

1. How do I determine if these messages are in fact read receipts instead of
messages generated by some form of malware? My Norton anti-virus program is
up to date and shows nothing, but it could be something not detected by this
program.

2. If the messages are read receipts (or not read receipts), why are they
being sent at all? At the time the 44 messages reported above were generated
I had the "Ask me before sending a response" option set, and I ALWAYS said no
when asked.

 

[Guest]

I have essentially the same problem. I notice it only because NAV pops up a
"scanning outgoing message" box. My first thought was a worm, but NAV never
reports one. I also thought of read receipts, but I have Outlook 2002 set to
always prompt, and that seems to be working -- I am occasionally prompted for
one. From other posts, I presume a delivery receipt would be handled by my
mail server and I would never see it locally.

I also have had several mail bounces which I suspect are related, they
typically look like they're going to a spammer from the name etc.

Characteristics:
1) Sent item not initiated by me, including read receipts
2) NAV reports scanning outgoing mail just as it would on a normal email send
3) Nothing in my Sent basket afterward
4) Mail bounces received with addressee not known to me & looking like
spammer; the reason varies, sometimes address not known or expired, but a
couple are more sinister: "Possible virus detected in text.zip" or "File
text.pif quarantined"

I come back to _some_ form of malware, whether it's a worm, spyware embedded
in an email, or hijacking Outlook from elsewhere? I run Ad-Aware SE every
few days, but I haven't seen a report that implied malware hijacking email.

The recent ones implying a possible virus attachment are worrying. I keep my
NAV 2005 up-to-date but nothing is perfect.

Any advice from the MS experts would be greatly appreciated!