Accessing attachments?

I now have a problem with accessing attachments from one of my regular emailers. Whereas I can go on to Outlook and access any attachments from all the rest of my regular emailers, with this one person the email comes through to Outlook without the attachment. I then have to click out of Outlook and use my internet browser to access the Yahoo!Xtra Pro Mail site where I can then access the attachment by clicking on the paper clip OR I can forward the email to myself and return to Outlook where I will now have the email complete with attachment which I can now access. Judy.