We currently have a hosted exchange 2003 service which we connect to using outlook 2007/2003 clients using RPC over HTTP. We have started to receive automated emails from a Yahoo Search Marketing service with zip file attachments. 4 out of the 5 emails sent consistently every time will report that the zip file attachment is corrupted or invalid, the other always opens fine. The file sizes range from 2 kb up to 80kb. We have tried switching cache mode off, creating new outlook profiles, saving the attachments to disk, uninstall AV/SPAM different zip archive applications etc with no success. The service provider has setup a test outlook profile and can apparently open the files fine using Outlook 2007 with RPC over HTTP. If I connect to the exchange service using IMAP from the same outlook clients the same attachments previously that would not open now do. This issue is experienced by all users who receive this file. All other zip file attachments are received fine we just experience this problem originating from this email source.
Thanks in advance
