I did a piece last December with some recorded sax parts that I did and it worked fine. I installed Windows 10 last summer. I also did the same piece in the 60 day trial of Sonar Platinum as a new mix with the same wav files in late February. That was the last time I really exported any sound files using Sonar. So, I believe the answer is yes, I have used the Mackie Onyx in Windows 10 both in Sonar X3 and Platinum but not a lot. The issue may have been precipitated by Sonar Platinum Trial or it may have even come from the new graphics card being added to the computer. 
The soundcard interface guit working after I tested it in Sonar X3 today. A system shutdown and restart did get the interface back and recognized by the Device Manager. I have a strong feeling that the issue maybe a failing soundcard that will eventually not work at all. This is the second Onyx Firewire I have had in the 1640 mixer. The first one died to after about 6 years of use (and after warranty, naturally) the second card was a friendly gift from Mackie support (minus shipping and handling :-)  ) since the system was no longer being made and they told me there were no more of those interfaces to be found at Mackie. I have seen them on eBay but they are still asking a high price for used ones with no guarantee they will last very long (the cards have to be as old as my last card that I got in 2010).
 
I have tried other mixes tonight and they are still working as exports and the sound card at the moment seems stable. I just hate to think of going out and spending another $grand on a new setup. (sigh)
 
 

"Firewire seems to becoming used less and less. being replaced by USB3 and Thunderbolt.
But for what its worth, I would continue using the Onyx with the Firewire card until it totally bits the shed."
 

That's a good line, I'll have to remember it. I am going hang on and hope it doesn't totally crash and burn. The Mic preamps and EQ on the Mackie Mixer would be missed as well. It is a good setup with good AD/DA converters on the firewire soundcard. But the mixer by itself would not work well going into a sound card that doesn't match its 18 outs (16 channels and 2 mains). I am spoiled.
 

great piece rich.
to me it sounds authentic. what I mean by that is now a day music using any kind of synths can sound robotic or thin.
this sounds all real. nice mix. I listened to it twice. really liked it.
Im now following you on soundcloud
 
Chuck

I like a Happy ending and good work Chuck. 
 
 

Brian, 
I would have changed the thread title long ago if I knew how to do just that, but I don't. Thanks for reading the thread and commenting. It is always appreciated.
 
 

Duh, that was easy. I appreciate the heads up on that Bristol_Jonesey and will remember that for the future when I type a thread title wrong and need to change it.
 
Thank you!!!