[imp] Attachment problems

[Diane]

One of my users is experiencing a problem with emailing attachments.

To quote:

"The problem is that sometimes after an attchment is added the e-mail will 
indicate that it has attempted to send but the message remains as a window 
having not successfully been processed. This has been happening with 
increasing frequency."

There is no record of the email having been sent in the Sent Mail folder.

He is the only user who is experiencing this problem.

Does anyone know anything about this; how to fix it or what is happening?

kind regards,
diane