I uploaded silly.docx as an attachment to a page. If I download it an .html extension is appended i.e. silly.docx.html. I get the feeling there is some sort of MIME type issue as I have heard that Safari may treat MIME types more strictly than other browsers? Of course the file size is different I assume as it gets downloaded as text instead of a docx zip-like thing. If the solution is to fiddle with core source or one of the bundled plugins I have that capability.
Confluence Sevrer 6.2.0