Problems Opening Attachments with Yahoo Mail

I’m experiencing what appears to be a compatibility issue with PDFs, Outlook and Yahoo Mail.

I use Outlook 2007 to send PDFs as attachments. I’m having problems opening the PDF attachments with Yahoo Mail. About 50% of the time Adobe Reader reports “There was an error opening this document. The file is damaged and could not be repaired”. I get the same error if I Open the file from the File Download window or Save then Open it. If I forward the message from Yahoo Mail back to my Outlook account I can open the attachment without a problem so something is happening during the Yahoo Mail download.

If I send the attachment using Yahoo Mail, instead of Outlook, the attachment can be opened. This would be a satisfactory workaround for sending PDF’s but if I use this approach for distributing forms I couldn’t use the Tracker to monitor who has and who hasn’t responded.

I don’t have an AOL account but I think the same problem exists with AOL sometimes because one of my users reported the problem on one of the same files that Yahoo has problems with.

These PDF’s are created using Acrobat Pro v9. I’ve encountered the problem with PDF’s and Forms. Sometimes I can correct the problem by recreating the PDF or form, but not always.

Does anyone have an idea what is going on?

Thanks,
Greg