We have an Exchange 2003 environment (on Server 2003) running Outlook 2003 as our mail client. Some users (at our site), are trying to send email messages to customers that are using Lotus Notes, if there is an attachment sent, it is stripped off at the Lotus Notes side. Some of our users at our site can send attachments to this specific customer and some can't. We have tried sending strait text messages (not HTML or Rich Text) but that doesn't work with some users. When our customer replies back to us to say they did not get an attachment, there is a "c.dat" file attached with their message. I'm not sure if this is an issue with Outlook or an issue with Lotus Notes...I would be happy to fix either one!