RME Babyface not recognized after driver/firmware update in Windows 8.1

Try a different USB port. For me, my device works ok in some of the USB 3 ports, but there are a couple on my machine it doesn't work properly with.

Thanks for the responses, unfortunately neither one seems to have made any difference. I was not able to get it working - so I removed the new driver and rollback to the previous one. At this point everything is working so I can live with it.

How did you manage to keep Windows 8.1.?.. I tried but eventually MS won the war. 

This damn thing is at again. In the middle of a session, Sonar reports that the Babyface was unplugged, and now it won't playback any audio. I tried everything, updating to the newest driver, roll back to previous driver. I had updated the firmware before and I not sure if there is a way to roll that back but I have exhausted every other possibility. It is not due to faulty wiring or unplugged chords or anything that obvious. Bottom line I have no audio interface right now. Nothing seems to work, at this point Windows cannot even use the device to play back system sounds and no DAW or standalone synth software that I have can use it as an audio capture, playback device. It lists there and install like it is there. I think the unit is faulty, there cannot be any other explanation. This is rather frustrating considering that it was working perfectly for the last few weeks. Was recording some really good sounding guitar tones and then voila, it just stopped working. I rebooted and worked for a couple of more hours and then did it again. Anyone have any other suggestions, I would appreciate it, thanks. As a last resort I am looking into rolling back the firmware, maybe that is a problem for Sonar and Windows I really do not know.

Thanks for the response, yes it still shows in Device Manager, and Windows reports it is working properly.
I do not have another dual cable like the one that comes with the unit to test it with, but I suppose I could try just a regular USB cable to see if it at least will work as a playback device. I will try that when I am back at home.

And please do another test to rule out the possibility (maybe unlikely, but who knows) that another app and/or Windows is trying to occupy Babyface's driver when SONAR is running:
 
In RME Driver Settings panel, click on WDM Devices Configure and uncheck all WDM Devices listed.
Do this both for Stereo and Multi-Channel.
 
Only ASIO is now available for applications like SONAR (I assume you're using ASIO driver mode in SONAR; if not, please do so, at least for the test).
 
Edit to add:
You mentioned Windows System Sounds.
 
It's recommended to disable them, because Windows will use your device at any time a System Sound will occur and change the sample rate on the fly if necessary which could lead to problems if you use a different sample rate in SONAR.