I have a customer who uses Outlook 2010; her colleague uses Outlook 2007. The email platform is Microsoft's 365 Exchange platform.
Following installation of a brand new Windows 7 desktop PC and a fresh installation of Outlook 2010, one of their large customers reported that he was no longer receiving attachments sent from the new PC. (However, other customers have not reported this problem).
Attachments then sent from her colleague, using Outlook 2007, were successfully received by the customer in question.
I installed Windows Live Mail on the new PC and the customer in question did successfully receive the attachments from an email sent from that email client.
The hosting company have looked at the problem and the PC (remotely) and they pointed the finger at Outlook 2010.
I have tried disabling various Outlook Add-ins (such as Avast Internet Security) but this makes no difference.
Has anyone seen this problem and can shed some light on possible causes?