It is on all excel files, or in one specific file?
If in one file, maybe this file is secure by IRM (right management).

Or filter on mail server block this type of file.
peter

"Mario" wrote:

When my boss attaches an Excel document to an email it will send and the
other person will receive it but when he right clicks on an Excel file and
chooses "mail recipient" or chooses mail recipient from the toolbar in an
"open" Excel file and tries to send it, the other person doesn't receive it
at all. Any suggestions why?