Well done Microsoft! You've killed the fax with Windows 2012 R2 and Windows 8.1!!! Hurrah!
Sarcasm aside, I'd be happy to see the end of faxes. It's dated and for the most part no longer needed, but some people are stuck in their ways I guess.
We recently deployed a Windows 2012 R2 server which required faxing, after a lot of messing around and rechecking everything from cabling, diagnosing the telephone line, swapping fax modems etc it came down to a driver file which is fubar in the latest release of Windows 2012 R2 & Windows 8.1.
Download and replace yours from here: