We are having issues where an email has a paperclip icon but not attachment in Outlook 2010.  If the same email is viewed via OWA, then the attached file can be seen and accessed, so I know there is a file there.

Is there a setting in Outlook or Exchange is blocking the attachment from making it through to the desktop client but not the OWA client? 

Hi,

• Sometimes Code Two Exchange Rules Users are facing the problem where an attachment icon is visible but it actually contains no attachments.

• If the message that was stamped with the signature by Code Two Exchange Rules is opened/replied/forwarded in OWA then it will appear in Outlook as the one that contains attachments.

Regards

Hi,

According to your post, I understand that a message display a paperclip icon but not attachment in Outlook, however its accessible in OWA.
If I misunderstand your concern, please do not hesitate to let me know.

Are all message with paperclip icon cannot display the attachment in Outlook?
How about run Outlook with Online mode?

Heres an article about difference between Outlook online mode and cache mode: https://technet.microsoft.com/en-us/library/jj683103.aspx
Meanwhile, I find an similar thread about your question. For your convenience:
https://social.technet.microsoft.com/Forums/exchange/en-US/478c326b-486b-461c-9141-dd544b245c75/outlook-20032007-cannot-see-attachments-but-owa-can

Thanks