Hi there, the problem you describe is what's called a Phantom Attachment. If you use AVG Anti Virus follow these steps:
Open AVG control center
select the e-mail scanner box
select plugins tab
select configure button
which opens a test options (window)
then under e-mail scanning check all six boxes,incoming mail,certify mail,with attachments only
outgoing mail,certify mail,with attachments only.
Also the plain text format must be checked.
If you dont use AVG then try this:
click on "Tools" in the upper left
choose "Options" from the menu.
When that loads, click on the "Read" tab.
Is the box next to "Read all messages in plain text"? If so try unchecking it
