Outlook 2003 plain text emails: attachments not readable

[Platypus]

Some people cannot read my email attachments. I changed the default email
setting to plain text, which is what everyone advises. The problem has
persisted, with not one but several different recipients. Is there any way to
overcome this bug?

 

[Pat Willener]

What means "cannot read my email attachments"? What kind of attachments?
Do they get an error? Are they able to open it? Is the attachment
data/text garbled?