Attachments are all converted to .ashx suffix vs. original file types like .docx or .xslx...
Firefox 8.0.x does not like our OWA (attachment.ashx)
UGA OIT says, there is a problem with attachments being viewed by the outlook web email system and Firefox 8. See below. Here are the three workarounds: 1) Right-clicking and renaming the attachment with the proper name and extension. 2) Revert to Firefox 7. 3) Use another browser.
Wšě wotmołwy (1)
Outlook Web Access sends an illegal Content-Dispositon header to Firefox. This is no longer allowed in Firefox 8. Firefox 9 will have a workaround for this so that Microsoft has time to fix their software.
See http://support.mozilla.com/nl/questions/895024
https://support.mozilla.com/en-US/search?q=attachement.ashx
Bug 704989 - add workaround for broken Outlook Web App (OWA) attachment handling
You can help us by sending a complaint to Microsoft and tell them that their software is broken.