bulrush:

Have you verified that other EMail receiving programs also don't show the attachment?

I'd suggest two things:

1. Send an EMail with an attached spreadsheet using a method that works well, and then compare the EMail with the one that doesn't seem to work. There could be a difference that gives you a hint.
2. Send the EMail to a gmail account or use a different mail client to view your EMail to see if the attachment shows up.

I haven't worked with EMail in some time, but I recall having a few difficulties with EMail attachments, too. I don't recall what the problem was, but it was something not particularly obvious at the time. (But it wasn't complicated, either.)

...roboticus

When your only tool is a hammer, all problems look like your thumb.