Windows 7 64-bit PC, running Outlook 2007 and Avast Free Antivirus v.7.0.1474. The Outlook avast! Addin is enabled.
Any Emails (imap) received within Outlook 2007 that have an attachment, e.g. a Calendar appointment, have duplicate attachments. i.e. 2 Calendar appointments appear. Please note, there are not duplicate emails, just attachments.
The email on the imap server only has 1 attachment, but in Outlook 2007 the email contains 2 attachments. This behaviour has been replicated on another PC running a similar setup.
Disabling the avast! Addin in Outlook 2007 and the duplicate attachment problem is resolved.
Turned off outbound scanning but it did not fix the problem.
The email is composed in Outlook 2007 and sent. To confirm, the email is received at the imap server correctly. Only when received in Outlook does the duplicate attachment appear.
This has fixed it everytime with my clients? Are you using an Exchange server? I remember there were some interaction issues with the Exchange Plug-ins under Tools, Security, add-ins. I will have to go through my notes, but I was unable to find that at this time. Here is what Microsoft did about A/V and Outlook in Windows 8 (completely new view):
I cannot reproduce this, and I have no clients after 10 years that have this. It has got to be something unique about your systems. We have avast! and Outlook 2007 on probably 10,000 machines, and we are not seeiong this. Again, I would lok at the Exchange add-ins. I remeber that they had caused some “undesireable” results in the past, but I am unable to reproduce that data. I would look there, 1st.